I myself have just bought the Denon in question, and am currently pulling my hair out trying to work through the setting up of it........not the connections etc....the finer tweaks. I am one of the consumers who moans like hell at having the manual only online and not on my lap in my living room in front of the home cinema setup that I am trying to set up.
I have just bought this to replace a Yamaha amp, the RX- V673. When i buy a new piece of kit, i tend to hate it for a while until i get used to the interface and ease of adjusting certain parameters that I find important.
But i never really was happy with the Yamaha. I considered it a huge let down from the old Sony model I had previously used for over 10 years. Main thing .....power. It was very agile with the movie side of things, the quality of the processing of the surround effects etc was impressive. It just didn't have grunt. I watch a lot of live music concerts, and i listen to metal. The Yamaha didn't have enough attack for me. I listen to things loud, and on the sony i never got to half volume and the house was shaking. The yamaha i nearly reached three quarters volume on a number of occassions and that's with the blu ray input level on maximum!! It felt too safe. I am hoping when I get the Denon going it doesn't let me down.
One thing is for certain, a good review in what hi fi isn't going to be indicative of how you feel about the product with your own eyes and ears in your own living room. I , like you mentioned, bought the Denon because i read it had power, it has the specs i need for my new ish 4k tv and ultra hd blu ray player, and i got it for £399.