Motorola took the wraps off Droid Razr, claimed to be the world's thinnest smartphone, recently. The Motorola Droid Razr not only weighs less at 127 g, it's also only 7.1 mm thick. As for the design, the Droid Razr is one sexy phone with a unique wavy pattern on the back.

Verizon Wireless started accepting pre-orders for Motorola Droid RAZR from Oct. 27 and consumers will start getting the phone by the second week of November.

The little phone will run Android's 2.3.5 Gingerbread mobile operating system. It will also probably be getting the Ice Cream Sandwich, Android 4.0 mobile OS upgrade, early next year. The 4G LTE enabled phone will feature a 1.2 GHz TI OMAP4430 dual-core processor and 1GB of memory.

The thinnest smartphone will certainly face stiff competition from Apple's iPhone 4S.

Though the iPhone 4S is not the iPhone 5 forecast by rumor mills, it is certainly not a lesser device. The phone has significant hardware upgrades even though it looks identical to the iPhone 4.

Apple has brought speech recognition to the masses with the 4S. The device is equipped with an intelligent assistant - Siri. The new smartphone received positive reactions from technology gadget reviewers especially for this piece of software.

The iPhone 4S has a 3.5-inch TFT Retina multi-touch display and is loaded with Apple's latest operating system, iOS 5. In addition, the phone comes with alternating antennae for better call reception, CDMA and GSM support, a personal assistant called Siri, iCloud and Bluetooth 4.0 wireless technology.

Here's a comparison of the features of the two contenders.

Size: Droid RAZR will come in 130.7 x 68.9 x 7.1 mm dimension and weighs 127 grams, while Apple iPhone 4S measures 115.2 x 58.6 x 9.3 mm and weighs 140 grams.

Display: Droid RAZR will come with a 4.3-inch qHD screen paired with Super AMOLED touchscreen that may give a resolution of 960 x 540 pixels with about 256 ppi pixel density. The iPhone 4S has a marginally smaller screen - at 3.5 inches - but boasts a Retina display of 960x640-pixel resolution at 326 ppi.

Operating System: Droid RAZR runs on the latest version of Google's smartphone Operating System, the Android 2.3.5 Gingerbread OS. It will also probably be getting the Ice Cream Sandwich, Android 4.0 mobile OS upgrade, early next year. Although the Android OS is capable of giving the user a very considerable amount of computing power, the fact that the Android apps market is cluttered with so many applications can make navigating it an annoying process.

Meanwhile, the iPhone 4S runs on iOS 5 - a free software update bringing over 200 new features to the iPhone, the iPad and the iPod touch, including wireless syncing, Twitter integration and widgets. The iOS 5 is touted as being very simple to use. The apps are arranged in grids of 12 across multiple screens, making navigation a potentially easier task.

Processor Droid RAZR will feature 1.2 GHz dual-core Cortex-A9 CPU, PowerVR SGX540 GPU, TI OMAP 4460 chipset with 1GB RAM. On the other hand, the iPhone 4S features a 1GHz dual-core ARM Cortex-A9 processor, PowerVR SGX543MP2 GPU and an Apple A5 chipset.

Camera: Both Droid RAZR and iPhone 4S sport a rear-facing 8-megapixel camera with 1080p HD video capture capability. 

Storage: Droid RAZR will have a fixed 16 GB internal storage and a 16GB microSD external card pre-installed that can be expanded up to 32GB. The iPhone 4S comes in 16GB, 32GB and 64GB models. It doesn't support a MicroSD card slot. Apple has not revealed the RAM capabilities of the iPhone 4S.

3G/4G Capabilities: Droid RAZR will come with Rev. A up to 3.1 Mbps, 4G LTE, HSDPA and HSUPA. The Apple iPhone 4S, on the other hand, has HSDPA 14.4 Mbps and HSUPA 5.8 Mbps support. The iPhone 4S also has CDMA EV-DO Rev. A (800, 1900 MHz) technology.

Battery Life: Motorola Droid RAZR has standard 1780 mAh battery offering talk time of up to 12.3 hours and standby time of 204 hours, while the iPhone 4S has a Li-Po 1,420 mAh battery, with 8 hours of talk time on 3G and up to 14 hours on 2G networks (GSM).

Price: Droid RAZR will be available on Verizon at $299.99, with a two-year contract. While the iPhone 4S costs $199 for the 16GB model, $299 for the 32GB model and $399 for the 64GB model with a two-year contract. Apple-listed prices for a contract-free phone in the United States are $649 for the 16GB model, $749 for 32GB and $849 for the 64GB.