The fact is, there is *no* such thing as a good DVD player for the Xbox. Having an additional one is a great thing, but please Team Ava -- don't take all the criticism to mean that you should stop developing the player! It's not good enough now, but it does have potential.
That said, I've only managed to get 1 (one) dvd to run with the player. Not very good. I tried Reg2 (like my dongle), Reg1 and Reg0 discs. The first one to run was a copy I made myself with DVD Shrink. Others just return me to the dash or start an infinite loop if auto-launch dvd is turned on.
I suspect that this is another MS DVD hack, since it's just as stupid when it comes to handling 4:3/16:9 content. It takes the screenmode from the dashboard settings, and doesn't auto-switch the television mode according to content. (Dunno if that's possible in the US, but with SCART it is in Europe -- anyhoo I thought the Ava guys were Norwegian). At least XBMC has that feature.... I hate to manually switch modes on the telly...
For me, the important features would be:
* Region-free
* Dongle remote support
* Automatic 16:9/4:3 switching, independent of dash
* Menu support
* Great pic quality, of course!
Don't care about hdtv modes, since they're not available here anyway.