Well, after magnifying the screen of the PSVita, it is now verified that it uses Super AMOLED Plus, not that crappy Pentile Matrix: regular Super AMOLED. The Plus mean it is regular RGB.
Look at the magnification of the pixel here:
http://www.edepot.com/playstation.html
Look at the magnification of the pixel here:
http://www.edepot.com/playstation.html