I may be flamed for this, but I really doubt there are a lot of differences between Denon and Marantz. They are owned by the same company, D & M holdings, and I would imagine this leads to shared resources. I think that Marantz is a brand that is more exclusive than Denon, but doesn't necessarily offer better performance. Denon by far is a bigger line for them, so I doubt it would make good business sense for them to hold back on those products. This is especially true given Denon products can get very expensive and esoteric for their top models. As for which you should choose, that's up to you. You would not need up conversion in a receiver if other devices you own or will buy can do it better. I've been very impressed with Audyssey XT, but there are mixed reviews on it's performance. In regard to expanded HDMI v1.3a ports with Deep Color, xvYCC and SACD support, I think this is the biggest feature you should look for on a receiver IF you are going to be using it as a video switch. You mentioned being future proofed. There is really no such thing in the world of receivers. They change almost every year. However, I would imagine all displays are going to be gravitating towards deep color, and I would want my receiver to be compatible.