The differences between the 4310CI were mainly the addition of the extra 2 HDMI inputs ports and an extra HDMI out port. From what I've read the upscaling using Anchor Bay which is supposed to be a vast improvement. They also have upgrades in other functions.

The only thing that concerns me is the weight. Denon 3808 which is 130W@8ohms weighs more then the Denon 4310 which I think has 140Watts@8ohms

Aside note - The 4310CI is an upgraded 3808CI not 3310CI as a lot of salesman people contend.