The Denon will be at least as good as the Sony STR-DG720 but if you want better sound you may want to step up to the AVR-X3200 that you should be able to get for well under 1K as the 3300 will be out in a few months. The 3200, being a current model, does have the latest features.
Or for just under $1,000, get one of this:
https://www.amazon.com/Marantz-SR70...qid=1466679644&sr=1-1&keywords=marantz+sr7009
This last year's model offers top sound quality and comes with Audyssey XT32. You won't have HDCP2.2, that affects 4K in certain way but may not be an issue for you.