There's really no glare to the PRS-900, a slight reflection in comparison to the Kindle 2. If you hold it at the right angle, than there's no difference. I gave the PRS-600 to my cousin this past September (well me & 3 other cousins split the cost 4 ways), anyway I had it for a week since I loaded books to it before giving it to her and the PRS-900 screen is less reflective than the PRS-600. I don't know anything about the Onyx Boox 60 since the IREX is the only other reader I considered due to my screen size specifications. That PRS-900 is truly awesome. It's almost the same size as the Kindle 2 (which has a 6 inch screen), in fact the Kindle 2 is bigger. If a person is in the US and can get around buying Amazon books without a Kindle then the PRS-900 is wayyyyy better!
This is really the size difference. I took the picture at this angle to illustrate that. They are almost the same height but the kindle 2 is almost an inch wider!
Kindle2, PRS-900