My experience with them has been positive. I get a slight amount of hiss from all my 5 speakers, but you have to get within an inch or two to hear it. The M-200's don't have anything to do with that in my case because only the front 3 are driven by M-200's; the surrounds are driven by a Yamaha receiver. The bottom plates of my 3 look perfectly normal, but I have seen pics of some that had some bowing. Transformer buzz is there, but not picked up at the listening position. In my case, I can't hear it unless I come within a foot of the top plate of the amps. And lastly, I've had zero problems with the auto turn-on mode. My amps have never came on without the receiver being on.