I have been using Audessey (in a Denon 4306) for the past 7 years, and it has its pros and cons. I have set up Audessey many times and have found out a few things along the way, which I will share. First, use as many positions as your receiver/processor allows. This really does improve things in the sweet spot, as well as making things sound better in the other seats. Use a mic stand or tripod. If your seat is higher than your ears, make sure the mic is higher than the back of the seat. (I actually weighed down the top of my seat with cloth-covered bricks so that I could have the mic exactly where my head is without changing the mic height.) Turn off the heater, phone, and anything else that will alter results. Do the calibration when no one else is home, if possible. After Audessey runs, adjust the crossover to where it should be, or to 80 Hz if you're not sure, and set your front speakers to "small." I know there are exceptions to this, but as a general rule, it is true. (A further suggestion: find good listening/speaker positions and then bass-trap your room, if possible. Then run Audessey again.)
Here is where I have a problem with Audessey and what I do to solve that problem. This program works wonders in tightening up the bass. It tames the room modes and allows the deep bass to come through cleanly without boom or muddiness. The bass sounds like real life! But Audessey devotes most of its computing power to the bass and, in my opinion, everything else suffers, whether in the Flat or Audessey selections. My solution is to use the manual EQ. I copy the base curve and then set everything above 500 Hz to 0 (i.e., no boost or cut). This will only work, by the way, if your subwoofer level closely matches your main speaker levels before you begin the calibration, so I run Audessey first so I can match the levels and then rerun it.
This is, I know, heresy. I know I lose the benefits of time alignment etc., but the tradeoff, for me, is worth it. I get clean bass and still get to keep the excellent sound of my Sunfire speakers. This approach is supported by many researchers who theorize that, above bass frequencies, equalization can do more harm than good. Equalization in the mids and highs will have radically different results in positions just a foot away from each other anyway, so what's the point? For those of you, like the starter of this thread, who hate Audessey, think about giving my approach a try. If your speakers are decent, it might be the solution to this problem. A better solution would be for Audessey to allow users (as Anthem does in its ARC) to set a maximum frequency for equalization. Someday, hopefully.