I bought an HK DVD 50 refurb on line without a hitch. At the time it was the only DVD that I could find having a changer, playing MP3 disks and progressive scan. Anyway, it works as advertised and worked flawlessly with the 1050 using an Outlaw PDO.
On the down side I wasn't able to get the 1050's remote to control the DVD 50. As to the DVD 50, itself, it has a few annoyances:
(1) Its operations is a bit on the slow. It take a while to read a disk and discover its type. I have no other experience, though, so it may be just like others.
(2) During some operations, it cannot be interrupted. This makes for poor feedback when using the remote (you're left wondering if it received the command or just ignored it).
(3) By default, it doesn't play all the discs loaded. You have to set it to repeat across all discs to get to play the next disk automatically when one finishes.
(4) The MP3 disk support is just barely usable and has been confused by some MP3s.
(5) (For me the worst since it seems like it would have been simple to fix) It cannot display the amount of time left on a DVD. This feature works fine for CDs, but not for DVDs.