I have a new iPad 3 - wifi only - 16G. I flew with it in bright FL sun from 1000 hrs to 1200 hrs over Central Fl (Cocoa Beach area). My aircraft is a RV8 with a Todd max tint canopy. I don't have my pad fixed to the airframe. Rather I use it like a paper map and keep it stuck in a side pocket or a footwell when not in use. There was no issue with seeing the screen clearly. Yes if you hold it just right you can get a specular reflection but you can do that with a ham sandwich also. I am most pleased with the iPad performance when using it in a gps referenced moving map mode.
Don
Don