I sent you a PM.
I can definitely recommend Denon only because I love what the Audyssey (XT Sub EQ and Audyssey XT Dynamic EQ) does for my system. I bet the XT32 in the X4000 does a better job.
That's really the only thing that separates any of these AVRs. Otherwise, in Direct mode, all these AVR would sound about the same in most cases. For example, the Yamaha would sound just as fabulous if you compare one Direct mode vs. another Direct mode. The separation only comes when you compare what Audyssey can do vs. what the other companies can do.
In case you are not aware, IMAX theaters, Phase Technology DARTs, Wisdom Audio, McIntosh, NAD, Marantz, Cambridge Audio, & Denon use Audyssey. Possibly potent stuff. I say "possibly" because not everyone is a huge fan.
I was not a fan of Audyssey at all until I started using the Audyssey Dynamic EQ feature. Again, YMMV.