Ok, well it's easy really to determine if it's different or worse.
Take a sheet of modern crisp bright white office photocopy paper.
A nice quality, clean white sheet and place it side by side with a white screen on either iPad showing a white screen.
The one with the cleanest white would be better would it not?
I know that generally grey's tend to show colour casts better.
The only real way would be to have an iPad up alongside a high quality correctly calibrated computer monitor such as a Dell U2711 and see how it stand up for matching colours.
After doing this, and thinking about it, andlooking at monitor calibration and comparing photos, the samsung screen is far superior. When comparing it to the lg like in my photongives a false impression that it is dull and yellow, but, the lg is actually calibrated completely wrong. It gives a false impression that the whites are whiter when actually the samsung produces true whites the lg looks so bluenon everything. I now prefer the samsung because videos andneverything look so much more vivid and rich and the lg one is cool and looks pretty much washed out on everything.