I have the 2910 and very happy with it.
I just got done watching Diana Krall "live in Paris" dvd in DTS surround... jaw to the floor.
The unit does multi channel audio very well.
I'd assume 3910 is even better.
If you decide to go Denon route, soon as you get it, do the firmware upgrade. It's available on Denon's site. Takes about 5 minutes to download, burn, and upload to your player.
Huge improvement in PQ on my player. No more green push and MB was all but gone.
Have fun hunting.