I did exactly what you are considering a while back, 8310 to 8900. I still have the 8310 but its been returned to its original box with all the stuff for it. Have not used it one time since I got the 8900. I think you will be pleased with the upgrade myself. Plus if you dont like it you can always go back to your 8310 (keep mine just in case) and sell the 8900, but I really dont see that happening.