Prior to the Bose PAS I was using passive JBL 15's with a Peavey powered amp. I never went to the trouble of A-B'ing the two systems because the Bose blew me away the minute I hooked it up and tried various presets.

The JBL's have been retired. And, even the little Samson Powered Speaker I depended on for those really small jobs has been gathering dust, despite the fact it is easier and quicker to set up.

Stereo/Mono has been a non-issue for me. Apparantly it is a non-issue for my audiences as well. I have had nothing but positive comments since becoming a Boser.
Eddie