A year ago I was just like you.
Then I had the possibility to listen at home to some of the "hottest" amp's in this price class -
take a look here. (Yamaha 3800, Onkyo 905 + Denon 4308 & 3808) I was very dumbfounded by how different they sounded with my equipment.
So after the one weekend test I had to believe in differences in amps sound.
But feel free to have your opinion - I'm basing my opinion on own experiences, as hopefully you are as well.
(And btw. With my equipment using the Onkyp 905 to listen to Moulin Rouge at higher volumes setted the standard of sound quality & feeling I want in my concrete bunker. Denon & Yamaha just couldn't reach that feelig. - Unfourtanately for me Onkyo sucked with all other material way bad.)
I read your interesting post a while back. I went ahead and bought the Denon but I wasn't influenced by your post. My decision was based on the following:
1. Noise - I cannot stand any audible hums and hiss as I listen to classical music.
2. Reliability - Based on my own experience as well as reading about others on various forums.
3. Features - I just love the WIFI thing.
4. Power - The only AVRs in the <$3K range that beats the Denon are the Onkyo/Integra ones.
5. Heat - Just warm, never hot.
5. Look - I don't like the look of the Onkyo/Integra.
Something interesting about your listening experience though, you mentioned the Denon worked well with all material, but not the Onkyo. Yet you said the Onkyo and Chicago was good but not with other material. That, to me, indicates your perceived differences in sound might have been due to not conducting a controlled comparison test. The thing is, if you simply switched your AVRs around in turns, and listened to different material in different times, your perception would have been influenced by many factors including even you mood, state of mind at the time, among other things.
I did appreciate your post back then, it was very informative and I did pay attention to things you mentioned, except for the difference in sound part as I do not believe in things like how one amp sound different in terms of "space" and I don't understand how one amp would sound better but only if you crank the volume up really loud etc. Thanks again (for the AVS post).