I've had my 3910 for about 5 years. It's connected to my 5805 via analog 5.1, HDMI, RGB, digital and DenonLink.
As of about a year ago it became very finicky about playing DVDs. It won't play most, even some brand new ones and other pristine discs. Recently I was able to get it to play a ripped and freshly burnt DVD but tonight I'm trying to watch Quantum of Solace on what looks to be a pristine DVD from Movie Galley and it will not recognize it. Display comes up 0h00m00s.
The machine has been playing CDs for me all day long no problem.
TIA,
Tim