While the new iPad has a few more things than the iPad 2, for example, retina display and a larger more powerful processor. A test from AnadTech shows that the iPad 2 gets better battery life.
The iPad 2 got an upgraded processor and the improved machine lasts a couple hours more than the original iPad 2 and the iPad 3. For $100 less ($150 if you get a refurb), you get more power. AnandTech tested the tablets performance in gaming, web browsing, and video playback, and found that this model was the last man standing each time.