I personally found the MCACC calibration had a negative impact on my speakers. When using any receiver processing via MCACC it killed the speakers vibrance. When checking the EQ, it removed the bass and treble, leaving the speakers sounding lifeless. Manually correcting EQ, made little difference, as the other processing effects still impeded the sound quality. I ran auto MCACC as well as adjusting every possible setting in manual MCACC, however none of the configurations did anything to improve sound while processing was applied. It had a very negative effect on the subwoofer especially, it set distance and speaker level on the sub incorrectly every time.
I called Aperion and spoke to both Jason and Oliver, their recommendation was to do a manual setup with no MCACC processing. I deleted all MCACC presets, did manual setup...speakers sound great. They indicated that calibration programs , be it from Pioneer or other manufactures often provide less than desirable results. I certainly found that to be the case with my setup.
I suggest you give it a shot, with and without MCACC and decide for yourself. In my case, MCACC had a negative effect on my speakers.