I have never had the opportunity to try a Crown amp. I was suggested the QSC brand by a friend musician. In his experience, he used all sorts of amps, and the only brand of amplifiers he couldn't kill was the QSC products. So I decided to go for that reputable brand.
I know that several of the audioholics have been using Crown amps and they have been satisfied. QSC amps have better specs but for practical purposes, the Crown are also reported as having an acoustical transparency. Then, it becomes a matter of personal preference. Also, the QSC products are more expensive and many audiophiles opt for the more affordable Crowns.