Having never heard them in a serious listening setting I can't say
whether these particular QSC amps sound bad or good for this purpose. I
can say that if they are convection cooled and designed to go in the
19" relay rack (in a reasonable number of rack units, i.e. height) the
semiconductor junction temperatures are higher than if they had the
large heatsink area in free air possible with high-end products and
will probably not last as long. Solid state amplifiers designed for
domestic use should have big heat sinks to keep the poewer devices
cool quietly.

It's likely they are significantly better than what you could get at
Wal-Mart, however, so that by Kroo's standards they are probably
excellent.