Generation 1 iPad, namely the iPad 1 use the A4 chip, screen resolution for 1024 * 768, memory for 256 MB. It has the advantage that price is cheaper, but it has no camera, the gyroscope, Siri, and so slow.
The iPad 2 used dual-core chip A5, screen resolution 1024 * 768, memory for 512 MB. It is cheaper than the new iPad. Unfortunately camera pixel of iPad 2 is low.
The third generation iPad uses A5X dual-core chip, screen resolution for 2048 x 1536, 1 GB memory. New iPad equipped with Retina screen, 5 million pixel camera, support network, 4 G Siri speech assistant, are faster; It is also higher price accordingly. In addition, the body is heavy.
See the above information, and if you have made a decision? which version blongs to you?