So I've had a Pioneer Elite receiver for the better part of five years now. All I ever did was a single 5.1 auto-MCACC calibration. Then, after I found a home theater forum, it suddenly occurred to me maybe doing an advanced calibration for just the two fronts and the sub might make a difference in how I listen to 2-channel music.
Yeah, I know, "DERP DERP DERP." The difference is startling, easily on the level of a component upgrade. And I got it for free!
So let that be a lesson to you. There's a reason why you get all those MCACC presets. Use them!