Upon further review I have changed my mind, the Onkyo has a USB on the back that supports MP3 playback from a flash drive or hard drive. Since both AVRs front USB is hidden behind the door I do not want to have the door permanently open with a USB cable plugged in going to the hard drive.
So this feature is the deciding factor for me.
The other AVR I have been looking at is the Pioneer VSX53, It had the early lead because I own a VSX23 and understand the way Pioneer does things, but it does not have a rear USB capable of playing files from a flash drive and the front USB is also behind the door.
I think the 3312 and the 809 will have equivalent sound and if both are set to flat (no processing) they probably sound exactly the same, both are highly rated by users and neither one is perfect in its functionality.
Video processing is not important to me as long as it can be turned off on the HDMI inputs.
The Denon can do the GUI overlay in 3D mode if that is important to you.