Should I stick to Audyssey or try Pioneer Mcaac?

Well, I am solidly in the Audyssey camp - I have Audyssey Pro that I use with my Denon. I am sure you will get mixed replies, but my opinion is that Audyssey probably has more R&D behind it.

I did own an Pioneer Elite AVR many years ago. I made the "mistake" of buying the service manual for it, which also was for the non-Elite version. I had thought that the Elite might have better "parts" but almost all had the same part number. The only exceptions were a couple of features that the Elite AVR added. Again, this was back in the Laserdisc timeframe, so things may have changed a lot since then. But at the time I asked myself why I spent the extra $s, other than the Elite version had pretty simulated wood end panels.

I love the looks of Pioneer receivers, I also think the class D amps they use in the high end receivers are great. Pioneers room correction is nice because they allow you to adjust the EQ settings after its been run however, its lacking simply because they dont focus any filters on the sub channel and thats a big one for most people.

That's one reason to not get MCACC because it does not eq sub but the receivers are nice looking.