Apple Inc.'s delay in launching the next version of the iPhone, the iPhone 5, has been Samsung Galaxy S2's gain as the ultra-thin smartphone recorded phenomenal global sales of 3 million units in 55 days in the UK and is expected to launch in four versions in the U.S.

The Galaxy S2 is super-thin, measuring merely 8.5mm (0.33-inch) in thickness and weighs about 4 ounces. These specifications beat iPhone 4's vital statistics as the Apple smartphone weighs 4.8 ounces and is 9.3mm (0.38-inch) thick.

Apple products are known for their beautiful design and their simplicity in the user interface, which is built around the device's multi-touch screen, including a virtual keyboard rather than a physical one.

Meanwhile, there is little doubt with the Apple's plan of producing 25 million iPhones units by the end of 2011, that the release of the next generation iPhone, dubbed iPhone 5, is around the corner.

Although smartphones running Google Inc.'s Android OS continue to gain share of total smartphone units sold, when it comes to profits, Apple remains the undisputed king, raking in roughly 50 percent of the entire handset industry's net earnings during the first quarter of 2011, Canaccord Genuity said in a note to clients, as reported by Apple Insider.

Below are the expected features of Apple's iPhone 5 in comparison with the Samsung Galaxy S2:

Operating systems: Samsung's Galaxy S2 runs the latest version of Google’s smartphone operating system, Android 2.3 Gingerbread OS. On the other hand, Apple’s iPhone 5 will be running on iOS 5, which is the newest of the OS versions. The new iOS 5 is expected come with 200 new features that will include Improved Notifications System, News Stand and iMessage.

Though Gingerbread isn't quite as refined as iOS yet, it has true multitasking support and is Google's best bet yet against iOS -- at least until it releases Ice Cream Sandwich. It is left to see which platform will outsmart the other in the long run.

Camera: Apple’s iPhone 5 is expected to have an 8MP dual-LED flash camera with 1080p video playback and panoramic photo capture, while iPhone 4 has 5MP camera with 720p video playback. The Galaxy S2, when compared, sports a rear-facing 8MP camera with 1080p video capture capability, and has an additional 2 MP front-facing camera for video chat.

Screen: iPhone 4 had a screen size of 3.5-inch with multi-touch display which will now see a major change with the upcoming iPhone 5. The new Apple iPhone 5 is expected to have a bigger edge-to-edge 3.7 to 4-inch curved glass screen. Galaxy S2 has a 4.3-inch Super AMOLED screen with 800x480 screen resolution.

Processor: Galaxy S2 is powered by a dual-core 1.2 GHz ARM Cortex-A9 Mali-400MP GPU Orion processor with 1GB RAM. Apple's iPhone 4 runs on 1GHz ARM Cortex-A8 processor, and the iPhone 5 is rumored to sport a 1.2-1.5 GHz dual-core A5 processor, which powers the iPad 2, with probably a 1GB RAM.

Storage: Galaxy S 2 boasts of 16/32 GB internal storage and via a microSD card slot it can expand up to 32 GB, while iPhone 4 has fixed 16/32 GB internal storage. Apple iPhone 4 doesn't have external storage, but that doesn't matter as 32 GB at the maximum is enough for the users. It is expected the iPhone 5 will have 16/32/64 GB internal storage.

Pricing: Apple’s iPhone 5 is expected to hit the markets in September and has been rumored to be priced at $600, while iPhone 4 is listed on Verizon at $649.99 on unsubsidized. The Galaxy S 2 is expected to be priced at $599 to $699 for an unlocked 16GB version, while the locked version to be sold on contract from U.S. wireless carriers is expected to be in the $250 to $300+ price range.

For a handset with such a broad range of standout features and specs, the Galaxy S2 is remarkably easy to summarize. It's the best Android smartphone yet, but more importantly, it might well be the best smartphone, period, Engadget said in its review.

Of course, a 4.3-inch screen size won't suit everyone, no matter how stupendously thin the device that carries it may be, and we also can't say for sure that the Galaxy S2 would justify a long-term iOS user foresaking his investment into one ecosystem and making the leap to another, Engadget added. Nonetheless, if you're asking us what smartphone to buy today, unconstrained by such externalities, the Galaxy S2 would be the clear choice.

Apple's iPhone features are extensively varied from Galaxy S2, which means loyal Apple fan base remains the same. And for Apple, there is no reason to fear a potential loss with respect to buyers.

Apple certainly knows how to surprise and already has a few things in place like iCloud which can steal the thunder from Android devices. It's the first time that Apple is not leading the pack but has to play catch-up with Android smartphones.

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