Auto-setup is important, especially after the hassle of manual setup with my current receiver (measuring distances and using sound-meter). While MCACC and Audyssey do essentially the same thing, Audyssey appears the better (AKA the enemy of good enough) because it samples 6 (or 8) listening positions in the calibration process. OTOH, Audyssey seems to be all or nothing, while MCACC can be adjused later to taste (less treble, more bass, etc). I can find no A/B comparisons, just subjective comments pro or con, often without hands on experience.
Auto-setup is outweighed by day-to-day convenience. My Denon occasionally decides to go from Dolby to a DSP Movie mode without user input; that's frustrating. Top on my list is reliability. My pre-Chinese-manufacture Denon has no other flaws other than that mentioned ... almost ten years of service! Numerous complaints about Onkyo took it off my list. Not so sure about these three, but Pioneer seems to have an edge at the moment.
In the end, it may be a dice roll; show-stopper, send-it-back, failures seem to run nearly 10% for these things.