Well, maybe not the ultimate, but you get the drift....
Room EQ is, IMO, the single most important differentiator between comparable receivers. Yet, there is very little information on how the various schemes compare to each other, how well they deal with taming the average room acoustics and in general, which ones work and which ones don't.
My personal experience is fairly limited: I've tried Audyssey XT (not XT32), Trinnov (the Sherwood R972 implementation) and MCACC, Microsoft's built-in room correction, as well as a couple of versions of Velodyne's built-in sub correction.
In my environment, every one of the above showed some improvement, but the one which stood head and shoulders above the others was the Trinnov. It was the most time-consuming to set up, but once the calibration was done, it provided hands down the best acoustic environment I have ever experienced in my TV room (which is, admittedly, pretty tough to tame -- floor to ceiling glass walls on two sides, hardwood floors and minimal furniture, resulting in significant lower frequencies resonance)
While all the others improved things to a varying degree, Trinnov is the only scheme which managed to make the room sound right. So, I love what Trinnov does.
Unfortunately, Sherwood has discontinued the R972 and I don't see any other receiver implementations of Trinnov on the horizon. So, I am thinking, what will I do if my R972 gives up the ghost?
I know there are also Anthem's ARC (which generally gets good reviews, Yamaha, Lexicon, Sony.... Sony has me actually intrigued as they appear to be doing something akin to Trinnov with their DCAC EX's speaker relocation and stereo calibration microphone. But again, there is virtually no information about it, other than the marketing materials.
It's amazing that there is so little information about Room Correction. There is even less in terms of meaningful comparisons between different schemes.
So, I thought to start this thread and see if others have more insight. Or, if anyone is actually interested