Mark Tremonti himself said it best that he was very hesitant about working with PRS and had to send his prototype sig back eight times because PRS guitars have "no bite." Apparently the workaround on his model was using compensating pickups.

Alex Lifeson (a longtime PRS endorser) has said in several interviews the same thing, he always liked the sound of his Gibsons better; that the PRS were too sweet and round sounding, however he couldn't get his Gibsons to stay in tune.

My personal opinion after playing many is that they are well built, with more attention to detail than other American-made guitars, but out of all the brands out there would be my last choice in sound, because the attack/cut/crunch lives in that upper register. To me they always seem like the quintessential dentist/lawyer guitars and I always had a suspicion that the thick filler/finish/clearcoat to achieve that jewel look was related to choking the tone.