As you noticed, the newer displays on the iMac and iPad are of a higher resolution and are much brighter and therefore more glossy than that of your older MBP.

I recently went from a 2008 MB to a 2011 iMac and noticed the difference right away. However, it doesn't seem to bother my eyes as it does with some other folks.

It may take awhile for you to become accustomed to the newer and brighter displays or you may need to wear computer glasses to cut down the brightness and glare.