We used one of these amps to replace a Crown digital which had failed in a typical digital way and was facing a serious repair bill. It was recommended to us as being a tried and tested amplifier design based on tested technologies to be long lasting, robust and reliable in true QSC fashion. It hasn't disappointed and has been running 24/7/365 for 18 months in that installation now without ever missing a beat.
The fan control keeps it quiet under normal operation. The sonic properties of the amp are well covered by the other reviews here and I agree with them, but in our application ease of installation, cost and long term reliability and repairability were our main interests and the amp performs very well against those needs.