Any mention of ATC usually brings up a lot of typical US audiophile forum nonsense from folks that have never had a proper demonstration of current product.
I'm a musician and I own ATC active monitors in my studio and ATC active tower speakers in my main listening room.
Ad copy or call it what you will, here's the official list:
ATC Client List
On the other hand, I know plenty of musicians that are as happy as can be listening to whatever they can afford, usually stuff that would make most of us get the heebie jeebies. And yes, that's the vast majority. Besides, most professional musicians these day are having a hard time meeting basic needs much less even a moderately priced stereo system. My older son is one of them.
Please keep in mind, those in the audience are hearing a completely different thing than the musicians playing on the stage. Live recordings are never made from the musicians perspective. I know several that think all my systems sound strange. One does this weird cupping thing around his ears, finally locks the hands in position and says, "now it sound like live music". I have no idea what't going on with him but I'm sure this perspective thing many have something to do with it.