I have received my PRS-600 last saturday. After a very long deliberation I decided I would give it a try despite the bad things I read about the screen.
I have a Cybook Gen 3 already and that has a very good and non-glaring screen but a very bad firmware update policy (see the threads in the Cybook forum). I was sick and tired of waiting for ePub support so I finaly ordered a PRS-600.
I was pleasantly surprised with the screen. It is not bad at all. Well, it's obviously not as good as the Cybook screen, but that's in the touchscreen technology. I expected it to be a lot worse. There is a bit of a glare, but that can disappear if you hold the device just slightly different against the light and the contrast is fine.
So, nothing wrong with it imho. I am very happy with my new Sony device.