All my gear is in a dedicated room. I play 2 channel music through my SP9 and front channels only. In MC mode my SP9 functions only as a pass through to the front speakers.
Although I could easily play everything in MC mode I don't. Music that was mixed and mastered to be played back in 2ch mode just sounds better that way. When I play MC sources I use MC in all its glory. MC through 4 ESL's 3 subs and a dedicated room can be very stimulating.