What's the story on auto sound calibration SSP's

For the SSP units that do offer home theater automatic room sound calibration with microphones, is it a big deal with substantial audio improvement than someone just setting up the audio manually? And which models offer it other than the Anthem D2?
Classe SSP-300 and SSP-600 offer this feature, but levels, especially for a subwoofer, may need to be tweaked manually.

Nevertheless, it works very well for me.
Many pre/pros have auto setup and some also have autoEQ (defeatable). The list is long.

It's funny how some technology seems new. A 13 year old Meridian 565 has a place in the set-up menu where you put in the measurement--distance--(how far from the chair;each speaker is). I can tell you it works well. Then,after this model-- no more manual set-up. With blueray and the use of analog inputs the calibration of sources is very different.
BTW I just set up my Onkyo 875. I listened first; then I just bumped up the center ch a taste and never used the microphone set up / and love the results in a 7.1 set up.