On the one hand, Denon can get newer features to market faster (the benefits of D&M's much larger R&D budget and the shorter product life cycles). On the other hand, there have been several people around here who have used both mid-level Denon receivers (including the $2000 Denon 4306, as described in some detail in
this old AVS thread ) and Model 1070's and found the 1070 to simply sound better. The 970/7075 may take a little more rack space, but it seems safe to say that it offers more sound quality value than a comparable Denon. Bottom line: I think you've already got a setup that can offer sound quality at least on par with (and likely better than) a $2000 Denon receiver for less first cost. Combine that with the upgrade advantages of separates, and it may be a better deal to stay put - you can always upgrade the 970 in a year or so to something comparable with newer features if the upgrade bug overwhelms you and keep the 7075.