Hi Axiomoholic,
To paraphrase a famous psycho-acoustical scientist and former president of the Audio Engineering Society world-wide (Dr. Floyd Toole), a pod of 4 microphones (Trinnov) or various measurement locations (Audyssey) are no match for two ears and a brain, and manual calibration with an SPL meter.
As has been pointed out, these systems are error-prone with bipolar or dipolar surrounds and subwoofers. They have their greatest utility with inferior non-linear speakers. And as Sir Quack has pointed out, they may sometimes be effective with certain rooms.
Certainly try them out if your receiver came with them, but do not rely on them or view them as a magical electronic "fix" that will somehow be superior to what you can accomplish with your ears, a pink-noise signal and an SPL meter. Compare the results from manual calibration with either Audyssey or Trinnov turned on, then off. With smooth, highly linear speakers like Axioms, the use of the auto-EQ functions of either Audyssey or Trinnov usually result in degraded sound quality.
Regards,
Alan
