I personally buy AVRs based on features. Of course sound quality is important, but I am unwilling to deal with exchanging receivers just to try to get better sound. And I mistrust judgements on sound quality in reviews. User opinions are even less trustworthy due to people's biases.
You may also want to take a look at the auto setup/room correction on the receivers. That seems like it could have a more substantial impact on sound than the analog signal path in the receiver.
Also note that AVRs often have glitches. Those can be important. For example, some people are pissed off that Yamaha receivers had an issue passing blacker than black over HDMI. That's just one example. These AVRs are getting complex, and manufacturers seems to be unable to to make an AVR without some glitch/annoyance.