Hackable with a firmware change/update.
Have a look on this site
http://www.cyberhome-help.de/main_english.php4
either English or German. They have a review of it, and compare it to the 512. It seems that it has a few glitches at the moment, but I see that there is a new firmware available (again from this site), which may fix some preoblems. They also have a forum, so have a look there to see experiences of this player.
There have been a couple of reports of similar problems on these forums for the 528, see http://www.dvd.reviewer.co.uk/forums/thread.asp?Forum=211&Thread=55629 - marcomarc`s comments.