Hi George,

 

Just another data point, but I stood on a sunny ramp with my friend, holding his iPad 1 next to my iPad 4 and neither of us could see any difference in brightness between the two screens.  However, I'd still recommend going with the latest iPad because of other benefits, such as speed and that Apple will support the iPad 4 longer than the iPad 2 or 3.  They've already given up on the iPad 1 and my friend has trouble with his iPad 1 locking up.

 

Best,

Dennis