There a cmd 121 at a club that I used to play at. I couldn't get a satisfying sound - this was after playing with the EQ and filters quite a bit. There was an ever present midrange honk which I suspect was caused by the tiny cabinet volume for a ported 12" speaker. I've had similar problems with cabs that are too small for the speaker. It did get loud though and didn't fart out. I like to hear some string growl so maybe if you eq all the mids and highs out this combo might appeal.
It took me a while to come around to the idea, but lately I've been plugging my preamp (Headway EDB-1) into the effects return. It sounds much better to me...