Having had the PRS-600 since last christmas, it started misbehaving over the last month or so. Sticky page turn buttons, screen fade in sunlight and strange battery performance. Add to this the screen reflection/glare annoyance, I had become somewhat fed up with it.
So I emailed the retailer, had a moan and asked for a full refund, which they gave me.
After some thought I decided to go for the PRS-650.
And I can't believe the difference in the screen clarity. It really shows how bad the PRS-600 was.
But one question, I read that the 650 was able to display fully justified text but all the books I've put on it aren't. The right hand edge is not justified.