I'm using the same AVR as John, and my results have been quite impressive. I almost exclusively use Audyssey in my admittedly simple room (relatively small and rectangular). Its results are much more immersive than any effort I've made to adjust by ear.
One thing to keep in mind is that Audyssey is designed to give you a fairly flat response curve. It will tame brightness that can be a problem in home theaters, but it will NOT accentuate the sub. Some people like a big, booming bass sound coming from the sub, and those people will need to adjust the Audyssey settings after the system does its job.
I do find that the system is very even sounding, the right amount of treble/mid/bass mix for my liking in most circumstances. But I do enjoy pumping up the sub a bit on occasion depending on what I'm watching or listening to (The "Love" DVD-A sounds great with pumped-up bass volume IMHO).