Apple is said to release its next-generation tablet device - iPad 3 -- in October.

The release date has been among a mixed bag of rumors involving iPad 3 as some reports ranged from September to mid 2012.  According to DigiTimes, it was reported that the third generation iPad will make a debut in September, and then hit stores by October.

LulzSec's hacked document from AT&T shows that the iPad 3 will be 4G-enabled. Apple had earlier announced that 4G would be enabled in both its iOS devices.

It is rumored that iPad 3 will have higher storage capacity, Thunderbolt I/O, a higher mega-pixel rear-facing camera and could possibly use fiber-in-matrix type material like carbon fiber reinforced plastic (CFRP), instead of aluminum.

However, when iPad 3 comes it will face stiff competition from a range of tablets running on a variety of platforms. iPad 3 will meet tablets based on new OS like webOS and QNX other than traditional rival Android.

Some of the major tablets are HP TouchPad, RIM PlayBook, Samsung Galaxy Tab 10.1, HTC Flyer and Motorola Xoom.

Let's take a look at the competing tablets in the market that may have to face the heat from iPad 3.