QSC has been Quilter from the very beginning.(
History of QSC Audio Products, Inc. – FundingUniverse). I've played a several of them and the only ones that I have found that have been really good are the professional touring amps. I bought one (CX1202v:
CX1202V) at a yard sale for $150 about 10 years ago. It was an install amp with all binding posts for inputs and outputs, so I had to modify the connections to handle 1/4" inputs and speakon outputs. It was something like 700 wpc at 8 ohms and full bandwidth with very low distortion figures. Insanely powerful and really good sounding. I made the mistake once of running it bridged (2200 watts at low distortion and full bandwidth) and I wasn't paying attention and my fEARful cabinet literally burst into flames. It was a serious beast. The guy selling had a gig installing PAs in stadiums and it was left over from a job (and was coincidentally the father of one of my law school classmates). I haven't liked their prosumer amps nearly as well.