Hi, I bought the S300 and have been using it for about 1 month. It sounded good out of the box, but after breaking it in it now sounds even better. I really like it and am keeping it. I have always been a tube guy and have never liked Transistor amps as much, but this amp is really good. Of course I am still using my CAT preamp so I still have some tube sound. I also bought 3 Isoacoustics Orea Indigo Audio Equipment Isolators to use under the amp and they also improved the sound. For the price this amp is a steal. I also like the idea of no maintenance.