The main difference between battlefield 3 and battlefield 3 limited edition is that the unlimited version has an additional "Back to Karkand" post-launch digital expansion pack. With Back to Karkand, you can wage all-out war on four of the most celebrated maps from Battlefield 2 including Strike at Karkand, Gulf of Oman and the Sharqi Peninsula.

Includes an expansion Back to Karkand
4 maps from Battlefield 2 including Strike at Karkand, Gulf of Oman, Wake Island and Sharqi Peninsula, all stunningly re-created using the power of Frostbite 2.
10 new weapons from BF2
3 new vehicles from BF2

Physical Warfare Pack --3 weapons
ps they will be available in original version of the game you just have to earn them

SPECACT Kit -- Players can expand their customizable options in Battlefield 3 with a set of eight unique multiplayer skins, one for each class in Battlefield 3.

Dog Tag Pack-- In Battlefield 3, dog tags serve as the player’s in-game signature, allowing gamers to customize their soldiers. Dog tags are displayed on screen every time a player takes down an enemy or claims an opponent’s dog tags. This pre-order exclusive item comes with five new, unique dog tags

The price

The difference is that Battlefield Limited Edition has additional features like weapons and vehicles. In addition, the Limited Edition comes with a code 4 which allows an expansion that is back to Karkland.