I'll put my two cents worth in also. I have had my Sony 505 for almost a year I think and have had no problems whatsoever. I have had a couple of books that were converted lock up the reader bur reconversion fixed the problem.
I love my BLUE Sony

and finally convinced my dad to buy one for himself and leave the old REB1100's behind. His has arrived already and is only awaiting his return home tomorrow to pick it up.