Actually, that's not true.
The primary differences between the iPad 3 and the iPad 4 are a 2X faster processor, a 2x faster GRAPHICS processor, 2x the amount of RAM. Also, the front-facing camera has been upgraded, the wi-fi is now dual-band for significantly better speed, and of course if you buy the cellular-equipped model you can use LTE -- which for many people is actually faster than their home connection.
Whether you think these things are worth the $130 difference between the 3 and the 4 is your own decision, but at least now you know what the real differences are.