Hey MMV! :wave:
Basically I've had two receivers by Yamaha in the past but long before Apex and my current apartment came along. My very first one was in the mid-90's (whose modelname I can't remember). A number of years (and other brands) later came the RX-V2600. This was before the days of Blu-ray and HD soundtracks. My current Denon AVR-3808 became the replacement in 2008 and has been with me since. It's a little difficult to compare the two brands in this context since the Apex speakers are fairly new with me, and I've never used them with Yamaha, only heard a short in-store demo with the RX-A3020. The thing I remember vividly from my old Yamaha's was the natural immersion and theater-like feel the brought with movies. Music was fairly good too, in fact a tad better than my current Denon even. I never bothered with YPAO though. It was a disappointment in my situtation at that time as I didn't feel it improved upon anything, I'm sure it must have evolved alot since though.
But when I got to try the Denon with Audyssey I was sold. The big advantage for me is without doubt Audysseys Dynamic EQ (not to be confused with Dynamic Volume), which no other system seems to have, and soundtracks became even more engrossing than with the Yamaha.
I wouldn't say no to testing the RX-A3020 in my home but currently I got my eye set on Denon AVR-4520 or Marantz AV8801. I actually haven't tested any other Denon model, but rather two models by Onkyo (TX-NR5009/10), also featuring Audyssey.