Apple Inc.'s iPhone 4S has generated an overwhelming response by consumers, but the smartphone has experienced battery-life problems for weeks now. Amid these continuing issues, the iPhone 4S is predicted to face tough challenges from Android devices such as the Samsung Galaxy Note, Samsung Galaxy S2 Skyrocket, Samsung Galaxy Nexus, Motorola Droid RAZR, HTC Vivid, and HTC Rezound or Vigor.

Early last month, Apple took the wraps off the iPhone 4S, instead of the highly anticipated iPhone 5. Nonetheless, the Apple smartphone officially sold 4 million units during its opening weekend.

Within a week of the device's release, however, there were persistent battery-life complaints from iPhone 4S users. And some Apple customers suggested that the iOS 5 mobile operating system has also had a negative effect on power usage by other iDevices. To rectify the issue, the company recently released its iOS 5.0.1 software update.

The iOS 5.0.1 update came more than a week after Apple first acknowledged that some users were running into problems with shorter-than-anticipated battery life after upgrading to the latest version of its iOS. The software update was designed to fix bugs affecting battery life, in addition to making three other key improvements.

Despite missing prominent specifications like edge-to-edge design, a larger display, 4G LTE, and near-field communication (NFC) technology, the iPhone 4S has some important features that were rumored to be part of the imaginary iPhone 5.

The features of the Apple smartphone include a 1GHz dual-core ARM Cortex-A9 processor, PowerVR SGX543MP2 GPU, Apple A5 chipset, and 8-megapixel camera. It also has a 3.5-inch TFT Retina multitouch display, and is loaded with iOS 5.

It also comes with alternating antennae for better call reception, CDMA and GSM support, a personal assistant called Siri, iCloud, and Bluetooth 4.0 wireless technology. The phone has a Li-Po 1,420 mAh battery, with 8 hours of talk time on 3G networks and as many as 14 hours on 2G networks (GSM).

Here is a list of the top smartphones that are potential winners against the iPhone 4S:

Samsung Galaxy Note

In September, Samsung unveiled its Galaxy Note with a huge 5.3-inch display, which is claimed to be the world's largest smartphone screen. Samsung said the Galaxy Note, which is a smartphone/tablet hybrid, will be available commercially in Southeast Asia this month.

Samsung has made the Galaxy Note with its huge display a revolutionary product with a screen that is larger than on the typical smartphone but smaller than on the typical tablet.

The new Galaxy Note combines the benefits of a notebook with the portability of a smartphone -- so business users get the best of both worlds, Simon Stanford, Samsung managing director for the UK and Ireland, told Sandra Vogel of BizGene.

Galaxy Note is adorned with a 1.4GHz dual-core ARM Cortex-A9 processor, Mali-400MP GPU, Exynos chipset with 1 GB RAM, and 5.3-inch Super AMOLED high-definition display that has 1280-by-800-pixel resolution with 285 ppi pixel density.

In addition, the phone runs on Android 2.3 Gingerbread with the Samsung S Pen interface, which is said to bring a selection of applications designed specifically for the included stylus.

Samsung recently confirmed the smartphone/tablet hybrid would be upgradeable to Google Inc.'s Android 4.0 Ice Cream Sandwich early next year. Ice Cream Sandwich is a combination of Gingerbread and Honeycomb in one unit.

Galaxy Note comes with 8-megapixel autofocus LED flash rear-facing camera with 1080p video capture and a 2-megapixel front-facing secondary camera for video chat.

The smartphone, available with either 16GB or 32GB of internal storage and expandable up to 32GB via a microSD card, has a Gorilla Glass display, Samsung TouchWiz UI 4.0 version, multitouch input method, accelerometer sensor for UI autorotate, touch-sensitive controls, proximity sensor for auto turn-off and gyroscope sensor. The phone measures 146.9 by 83 by 9.7 mm, and weighs 178 grams.

Additional features include Bluetooth 3.0 version with HS, microUSB version 2.0, USB On-the-Go, 4G LTE, HSDPA 21 Mbps, HSUPA 5.76 Mbps support, Wi-Fi 802.11 a/b/g/n, DLNA, Wi-Fi Direct, Wi-Fi hotspot, A-GPS support, S Pen stylus, NFC, active noise cancellation with dedicated mic, TV-out (via MHL A/V link), SNS integration, digital compass, MP4/DivX/XviD/WMV/H.264/H.263 player, MP3/WAV/eAAC+/AC3/FLAC player, Adobe Flash 10.1 support, Samsung ChatON, and barometer sensor. Its standard battery is Li-ion 2500 mAh.

The unlocked version of the Galaxy Note is available from Amazon.com at a price of $849.99 with free shipping.

Samsung Galaxy S2 Skyrocket

The Samsung Galaxy S2 Skyrocket, a follow-up to Galaxy S2, was made available at AT&T on Nov. 6. The Samsung Galaxy S2 LTE, dubbed the Skyrocket, along with the HTC Vivid, would be the first AT&T 4G LTE (Long Term Evolution)-capable smartphones.

The Skyrocket touts a 4.5-inch Super AMOLED Plus display that may give a resolution of 800 by 480 pixels with about 207 ppi pixel density. It measures 129.8 by 68.8 by 9.5 mm, and weighs 130.5 grams.

Running on the Android 2.3.5 Gingerbread OS, the Skyrocket comes with a 1.5 GHz Scorpion dual-core processor, Adreno 220 GPU, and Qualcomm APQ8060 Snapdragon chipset with 1 GB RAM.

It also comes with an 8-megapixel autofocus LED flash rear-facing camera with 1080p video capture and a 2-megapixel front-facing secondary camera for video chat.

The smartphone, with 16GB of internal storage that is expandable up to 32GB via a microSD card, has a Gorilla Glass display, Samsung TouchWiz UI 4.0 version, multitouch input method, accelerometer sensor for UI autorotate, touch-sensitive controls, proximity sensor for auto turn-off. and gyroscope sensor.

Other features include Bluetooth 3.0 version with HS, microUSB version 2.0, 4G LTE, HSDPA 21 Mbps, HSUPA 5.76 Mbps support, Wi-Fi 802.11 a/b/g/n, DLNA, Wi-Fi Direct, Wi-Fi hotspot, A-GPS support, active noise cancellation with dedicated mic, NFC support, SNS integration, digital compass, MP4/DivX/XviD/WMV/H.264/H.263 player, MP3/WAV/eAAC+/AC3/FLAC player, and Adobe Flash 10.1 support. Its standard battery is Li-ion 1850 mAh.

At AT&T, the Skyrocket is usually available for $249.99 under a two-year contract. In certain markets, however, AT&T is discounting it $100, bringing the price down to $149. At Amazon.com, the Skyrocket is available for $189.99 with a two-year AT&T contract.

Samsung Galaxy Nexus

Google and Samsung unveiled Galaxy Nexus, the first phone running on Android 4.0 Ice Cream Sandwich, at an event in Hong Kong on Oct. 18. The phone is expected to arrive in the United States late this month.

Ice Cream Sandwich is a combination of Gingerbread and Honeycomb in one unit. Android's head of engineering, Mike Claren, announced that the new OS is Google's most ambitious release to date.

Features arriving with Android 4.0 include widgets in a new tab; a customizable launcher; Gmail with offline search, a two-line preview, and a new action bar at the bottom; better voice integration; improved copy-and-paste functionality; and a new tabbed Web browser that allows up to 16 tabs.

The Galaxy Nexus -- measuring 135.5 by 67.94 by 8.94 mm, and weighing 135 grams -- is also known as Samsung Google Nexus Prime, Samsung Google Galaxy Nexus I9250, Samsung Google Nexus 3, and Samsung Google Nexus 4G.

The Galaxy Nexus is equipped with a dual-core 1.2GHz Cortex-A9 CPU, TI OMAP 4460 chipset, 4.65-inch high-definition Super AMOLED display with about 316 ppi pixel density, 1GB of RAM, 16GB or 32GB of internal memory, NFC support, 5-megapixel rear-facing camera with 1080p video capture, and 1.3-megapixel front-facing camera for video calls.

The smartphone has an oleophobic surface, a multitouch input method, an accelerometer sensor for UI autorotate, touch-sensitive controls, a proximity sensor for auto turn-off, and a three-axis gyro sensor.

Among additional features are Bluetooth 3.0 version with A2DP, microUSB version 2.0, 4G LTE, HSDPA 21 Mbps, HSUPA 5.76 Mbps support, Wi-Fi 802.11 a/b/g/n, dual band, DLNA, Wi-Fi hotspot, A-GPS support, NFC support, active noise cancellation with dedicated mic, digital compass, MP4/H.264/H.263 player, MP3/WAV/eAAC+/AC3 player, and Adobe Flash support. Its standard battery is Li-ion 1750 mAh.

There was a Costco screenshot that showed a price of $289.99 for Galaxy Nexus, leading many to believe that the Samsung smartphone would be priced around $299, akin to its Android cousins on the Verizon network.

Motorola Droid RAZR

Motorola unveiled the Droid RAZR, claimed to be the world's thinnest smartphone with a mere 7.1 mm thickness, on Oct. 18. The phone was available on the Verizon network at 11:11 a.m. on Friday.

The Droid RAZR, running on the Android 2.3.5 Gingerbread OS, comes with a syncing system called MotoCast, which, according to Motorola Mobility President Sanjay Jha, is the phone's most important feature.

You can stream content from your computer straight to your pocket [or purse] so your personal content is always within reach, the company said in a press release.

The Droid RAZR is adorned with a 1.2 GHz dual-core Cortex-A9 CPU, PowerVR SGX540 GPU, TI OMAP 4430 chipset and 4.3-inch Super AMOLED display that has qHD resolution with pixel density of about 256 ppi. It comes with 1GB RAM and 16GB ROM.

It features WebTop interfaces like the Droid Bionic, Atrix, Photon, and others. Thus, to run the full Firefox browser, the user can tie it up to one of Motorola's lapdocks.

The phone comes with 8-megapixel autofocus LED flash rear-facing camera with 1080p video capture and a 1.3-megapixel front-facing secondary camera for video chat.

The smartphone, with its 16GB of internal storage and 16GB microSD external card preinstalled (expandable up to 32GB), has a Gorilla Glass display, multitouch input method, accelerometer sensor for UI autorotate, and proximity sensor for auto turn-off. The phone measures 130.7 by 68.9 by 7.1 mm, and weighs 127 grams.

Additional features include Bluetooth 4.0 version with LE+EDR, microUSB version 2.0, 4G LTE/HSDPA/CDMA support, splash resistance, HDMI port, SNS integration, digital compass, Wi-Fi 802.11 b/g/n, assisted GPS, eCompass, simultaneous GPS, GLONASS, MP3/AAC+/WAV/WMA player, and MP4/H.263/H.264/WMV player. Its standard battery is Li-Ion 1780 mAh.

At Verizon, the Droid RAZR will be available for $299.99 under a two-year contract. Amazon.com ran a special offer only for Friday, when the Droid RAZR was available for $111.11 with a two-year Verizon contract.

HTC Vivid

On Nov. 6, AT&T released the long-awaited 4G LTE smartphone HTC Vivid on its network

The Vivid, running on the Android 2.3.5 Gingerbread operating system, features a dual-core 1.2 GHz processor and 4.5-inch qHD display with 960 by 540 pixels of resolution and about 245 ppi pixel density.

It is officially known the phone would be upgraded to Android 4.0 Ice Cream Sandwich after the holiday season.

The HTC Vivid is one of the first smartphones able to use both LTE and HSPA+ 4G speeds, which allow owners of the smartphone reliable connections via both in areas where applicable.

Measuring 135.5 by 67.9 by 8.9 mm, and weighing 135 grams, the HTC Vivid features an 8-megapixel dual-LED flash camera with 1080p video capture and a 1.3-megapixel front-facing secondary camera for video chat.

The smartphone, coming with 16GB of internal storage and expandable up to 32GB with a microSD card, has multitouch input method, accelerometer sensor for UI auto-rotate, proximity sensor for auto turn-off, HTC Sense UI, and touch-sensitive controls.

Other features include Bluetooth 3.0 version with A2DP, microUSB version 2.0, 4G LTE, HSDPA, HSUPA, Wi-Fi 802.11 b/g/n, DLNA, Wi-Fi hotspot, SNS integration, digital compass, MP3/AAC+/WAV/WMA player, MP4/H.263/H.264/WMV player, and A-GPS support. Its standard battery is Li-ion.

At AT&T, Vivid is usually available for $199.99 under a two-year contract. In certain markets, however, AT&T is discounting it $100, bringing the price down to $99.99. At Amazon.com, Vivid is available for $159.99 with a two-year AT&T contract.

HTC Rezound or Vigor

The HTC Rezound, aka the HTC Vigor, may be on the way to the market. Droid-Life has captured a somewhat deformed shot of HTC Rezound via a Verizon ad that went live too soon.

The phone from the HTC camp, expected to hit Verizon's 4G LTE network on Nov. 14, is rumored to sport a 1.5GHz dual-core processor. It will run on Android Gingerbread juice.

The phone, touted to be a replacement for the HTC Thunderbolt, is expected to feature a 4.3-inch display with 1280 by 720 screen resolution and about 342 ppi pixel density.

The Vigor is surmised to be fitted with an 8-megapixel dual-LED flash camera with 1080p video capture and a secondary camera for video chat. It is expected to come with the HTC Sense version 3.5 user interface.

It is also expected to offer 1GB RAM and 16GB of internal storage. It also may incorporate Beats Electronics Technology -- best known for the high-performance line of headphones backed by the hip-hop artiste/producer, Dr. Dre.