Samsung Galaxy S2, the smartphone touted by some as an iPhone Killer, is finally coming to the United States this week after becoming the best-selling Samsung phone ever.

Galaxy S2, which runs on Android 2.3 Gingerbread OS and sports Samsung's TouchWiz UI, is coming to Sprint's network on Sept. 16 as Samsung Epic 4G Touch version, while AT&T would launch Galaxy S2 version on Sept. 18.

The Samsung smartphone comes with an 8-megapixel camera with flash and can record HD video in 1080p offering the richest video content on a smartphone. The phone also has the front-facing 2-megapixel camera for video chat.

All the versions of Galaxy S2 will get 4G treatment, offering data speeds up to four times faster than what is expected in Apple's forthcoming iPhone 5. T-Mobile and Epic 4G Touch version of Sprint has 4.52-inch display screen whereas AT&T version retains 4.3-inch screen of original Galaxy S2 version sold worldwide.

The Sprint and AT&T version of Galaxy S2 is powered by a dual-core 1.2 GHz ARM Cortex-A9 Mali-400MP GPU Orion chipset, while the T-Mobile version will be powered by a 1.5 GHz dual core Qualcomm APQ8060 processor. The phone comes in 16/32GB internal memory configuration with 1GB RAM.

As for Apple Inc.'s iPhone 5, most features are attributed to the realm of rumors but some are more likely to be in the phone than others. For sure, the iPhone 5 will feature the latest iOS 5 operating system, the A5 processor found in the iPad 2, an 8-megapixel camera and a slimmer and thinner design.

Apple’s iPhone 5 is seeing “unprecedented demand” ahead of its release, which is rumored to come in October, according to a recent survey conducted by RBC Capital Markets. The data showed that 31 percent of the respondents were very/somewhat likely to buy the iPhone 5, significantly exceeding the pre-launch iPhone 4 demand of 25 percent.

In the second half of 2011, the heated battle will be between the iPhone 5 and Galaxy S2. Both of these smartphones are right up there in the hype clouds, and hopefully they can both live up to it.

Here is a look at 10 reasons why the Galaxy S2 will score over the iPhone 5.

Operating System: Apple's iPhone 5 is expected to come equipped with the recently announced iOS 5. The important features of iOS 5 are already found in Android, except iMessage that is mostly copied from RIM's BlackBerry. The iOS 5 important features include the notification bar, cloud synchronization, wireless syncing, Twitter integration and Widgets.

In recent days, Android 2.3 Gingerbread OS is used in smartphones and Android 3.0 Honeycomb OS is used in tablets. But the next version of Android called Ice Cream Sandwich will be a single OS running across smartphones and tablets.

Google's executive chairman Eric Schmidt confirmed in an interview with Marc Banioff at’s conference, Dreamforce, in San Francisco, about the rumours of Ice Cream Sandwich, which was previewed at a Google conference in May.

We have a new operating system, internally known as Ice Cream Sandwich for some reason, which is being released in October or November, which everyone is really excited about, Schmidt said.

Ice Cream Sandwich will bring all the interface loveliness of Android Honeycomb to smartphones including updated app launcher, holographic user interface, interactive and new home-screen widgets plus the multi-tasking panel.

The Ice Cream Sandwich OS will definitely help reduce the majority of the fragmentation issues on Android devices. Android is more customizable, has more widgets, less restrictions, is more functional and will feature a more fluid interface. The iPhone 5 is going to have to top this in order to do better.

Processing Power: The Sprint and AT&T version of Galaxy S2 is equipped with dual-core 1.2 GHz ARM Cortex-A9 Mali-400MP GPU Orion chipset, while the T-Mobile version will be powered by a 1.5 GHz dual core Qualcomm APQ8060 processor. It is backed by 1 GB of RAM. This is almost equal to the processing power of a desktop machine.

Meanwhile, the iPhone 5 is expected to come with the iPad 2's processor but it is doubtful if it would exceed the 1.2 GHz barrier. With improved versions of Galaxy S2 about to feature 1.5 GHz processor with 3D graphics support, iPhone 5 needs more to match up to Samsung’s flagship phone.

Display: Super AMOLED Plus display is considered to be the best available technology for mobile displays. Samsung is the only manufacturer of Super AMOLED Plus displays and if one wants to experience the best screen there is no other choice in the market.

The Super AMOLED Plus display helped Samsung Droid Charge to become one of the best selling devices on Verizon, overtaking HTC Thunderbolt. The iPhone 5 will just be an improved version but still will not be able to match Super AMOLED Plus.

The Super AMOLED Plus display delivers superior color, enhanced readability, slimmer form and better battery consumption than the previous generation. The Real-Stripe panel technology brings 30 percent more pixels per inch for a brighter, clearer and richer viewing experience compared with the first-generation AMOLED. Also it uses less space and consumes 18 percent less energy than previous displays, making it one of the longest-lasting smartphones available.

Galaxy S2 will be coming to AT&T with a 4.3-inch screen, while the T-Mobile and Epic 4G Touch version of Sprint has 4.52-inch display screen. The Epic 4G Touch comes with 4.52-inch (about 206 ppi pixel density) 800 x 480 pixels Super AMOLED Plus capacitive touchscreen display.

The Apple iPhone 5 is expected to feature a 3.7-inch or 4-inch display according to different case designs. At a minimum of 4.3 inches, Galaxy S2's display dwarfs the upcoming iPhone 5. With major smartphone manufacturers opting for 4.3 inches as the ideal screen for their phones, it will be interesting to see what comes out on the new iPhone 5.

Design: Apple's iPhone 5 will be just an upgrade of its previous versions. When it comes to the Galaxy S2, the very delay in reaching the U.S. shores shows that Samsung is prepping various designs with improved modifications and specs with different carriers.

The latest report shows that T-Mobile, AT&T and Sprint are going to offer their versions of Samsung Galaxy S2. Sprint unveiled its Samsung Galaxy S2 version known as Samsung Galaxy S2 Epic Touch 4G, which retains all the basic specifications of the Galaxy S2, except for the 4.5-inch display.

The AT&T version will retain the 4.3-inch display, whereas the T-Mobile version has not received any official name, but the Hercules is expected to come along with 4.5-inch screen.

Verizon confirmed that it will not be offering the Galaxy S2 on its network, but would opt for Samsung Droid Prime to grow its Long Term Evolution lineup. In fact, according to Boy Genius Report, Verizon is worried that the Galaxy S2 will not be able to compete with the iPhone 5 when it is launched.

Hence Verizon is expecting Droid Prime to become its ultimate Android flagship phone which will most likely be the first phone to feature Android 4.0 Ice Cream Sandwich operating system, giving stiff competition to the iPhone 5.

Samsung recently said it will be launching the Galaxy S2 lineup with an LTE version, but that would most probably not go to Verizon. The Galaxy S2 LTE version will have 4.5-inch Super AMOLED Plus display, Android 2.3, LTE with HSPA up to 42 Mbps, 8-megapixel camera, 1850 mAh battery and a 1.5 GHz dual core processor, and will come equipped with 3D games and videos, as well as the ability to browse web pages like Google and YouTube with ease.

Security: The approaches for Android and iOS security are different. Apple verifies all the apps before allowing it onto App Store to prevent a virus, but the rest of the phone is semi-vulnerable. Although Android does not check the apps, the apps are run in an isolated way so as not to affect the system in the event of a virus attack.

Both Android and iOS require you to sign in with some form of an account in order to download/install apps from the applicable store/marketplace. For iOS, you use your iTunes account. For Android, you use your Google account.

According to a recent Symantec report, even though iOS and Android both have their weaknesses, the mobile platforms are still much more secure than their PC counterparts.

Researchers have found many more vulnerabilities on iOS than Android. Roughly 200 have been found on iOS, compared to only 18 found on Android. Only 4 of those 18 remain unpatched by Google. Google is also faster than Apple when it comes to patching a vulnerability, averaging 8 days to Apple's 12 days.

Both the operating systems are vulnerable to viruses, but the Android has an antivirus app which iOS does not have. Hence Samsung Galaxy S2 holds an advantage over the iPhone 5.

Flash: Flash is a major drawback in the iPhone. The Samsung Galaxy S2 supports Flash. The Galaxy S2 supports full HD video playback inside Adobe Flash player. There is no other device at present which allows full HD video playback even inside Adobe Flash player.

According to Apple, Adobe Flash is a big security risk, not to mention it crashes lots and kills your battery life. Rather than using Flash, Apple has adopted HTML5, CSS and JavaScript – all open standards. Apple’s mobile devices all ship with high performance, low power implementations of these open standards.

Flash was created during the PC era – for PCs and mice. Flash is a successful business for Adobe, and we can understand why they want to push it beyond PCs. But the mobile era is about low power devices, touch interfaces and open web standards – all areas where Flash falls short, Steve Jobs said in a statement.

The flood of media outlets offering their content for Apple’s mobile devices demonstrates that Flash is no longer necessary to watch video or consume any kind of web content. And the 250,000 apps on Apple's App Store proves that Flash isn't necessary for tens of thousands of developers to create graphically rich applications, including games.

Jobs said new open standards created in the mobile era, such as HTML5, will win on mobile devices (and PCs too). He said perhaps Adobe should focus more on creating great HTML5 tools for the future, and less on criticizing Apple for leaving the past behind.

Near Field Communication (NFC): Samsung Galaxy S2 supports the NFC chip that allows for simplified transactions, data exchange and connections with a touch. As of now, NFC is just a rumor for iPhone 5 and most probably Apple won’t be embracing the technology, since Near Field Communication has no industry standards.

Given that its main smartphone rival is offering the mobile payment service, Apple may have harbored thoughts of integrating the new technology in the soon-to-come iPhone 5 in order to remain competitive in the market.

NFC allows for simplified transactions, data exchange, and connections with a touch. A smartphone or tablet with an NFC chip could make a credit card payment or serve as keycard or ID card.

Globally, 100 million people use mobile payment outside the U.S., but only 3.5 million use the technology in the U.S. As of now, NFC is just a rumor for the iPhone 5 and most probably Apple won’t be embracing the technology, since Near Field Communication has no industry standards.

It is said that Apple has disclosed in some of the meetings that NFC won't be on the feature list of the next iPhone. The Independent, citing some of the largest mobile carriers in the UK, said that Apple will forego NFC in its next iPhone due to lack of industry standards about the technology.

Connectivity: Galaxy S2 already supports 3G data speeds up to 21 Mbps (HSPA + networks), but with the Galaxy S2 LTE version poised to feature HSPA up to 42 Mbps, the iPhone 5 doesn’t stand a chance in terms of speed.

Also, the Galaxy S2 offers Bluetooth 3.0+HS transfer, Wifi Direct, Allshare (DLNA) and HDMI through MHL. Unlike Apple iOS, where you can’t even transfer the pictures taken with the camera through bluetooth, there is no restriction here. You can transfer files through high-speed Bluetooth (it is the only device at present that supports true 3.0+HS standard), or Wifi Direct.

Using Allshare, you will be able to stream multimedia content wirelessly to any device that supports DLNA (you can use XBMC media center software in your computer as well). Kies Air enables you to manage the phone content wirelessly without any software or driver. It also supports UBS on-the-go so that you can connect other USB storage devices directly to the phone.

Watching all one's content on a big screen is something that one could often take advantage of. With the Samsung Galaxy S2 MHL connection with TV, you can do it at full-HD 1080p resolution (with up to 30 fps).

Battery and Memory: Galaxy S2 has the privilege of expandable memory and a removable battery. Apple's iPhone versions differ from other smartphones in the market in terms of removable storage as none of them have featured one.

In terms of RAM memory, Apple never reveals its capacity and it always turns out to be less than other phones. Hence, the Galaxy S2 holds the advantage of 1 GB RAM to match the dual core processor.

If the iPhone 5 does feature 4G support, then that alone will reduce the battery life of the iPhone 5 to less than 8 hours. Galaxy S2's battery life is not the best on the face of the planet, but it easily lasts a day with good use and can stretch out to two days with mostly calls and texting.

If the Galaxy S2 was used all the time then a user will be lucky to get 10 hours of battery and that's with the enhanced 1650 mAh battery widget on board, according to review.

Apps and open source: The Android market has improved in quality and quantity over the past few years and is expected to surpass the App store. The biggest plus point about Android apps is that majority of the quality apps are free.

Android Market is an online software store developed by Google for Android OS devices. Its gateway is an app called Market, preinstalled on most Android devices, allows users to browse and download apps published by third-party developers.

Anyone can get access to the source of Android to better the system. If any weaknesses are found in the open source community, they are quickly fixed.

Though Apple's iOS is not an open source, 200 million users have downloaded over 15 billion apps from Apple's App Store. As of May 2011, Apple approved its 500,000th app.

After the success of Apple's App Store, and the launch of similar services by its competitors, the term app store has been adopted to refer to any similar service for mobile devices. However, Apple applied for a trademark on the term App Store in 2008 which was tentatively approved in 2011.

The iPhone 4 was criticized for antenna-gate issues. Apple said the device’s antenna issues were related to software and not the hardware, eliminating the need to recall the device, but it took months to resolve the issue.

It is yet to be seen how Apple's iPhone 5 will fare against Samsung Galaxy S2.

Must Read: Samsung Epic Touch 4G Joins Motorola Droid Bionic’s Party To Rival Upcoming iPhone 5