A friend of mine is looking at the Sherbourn 5/1500a Power amp (5x200w) and asked me if there was any other products out there that would be a big step up in sound quality. He also noted that some much more expensive amps are lower in power than the Sherbourn and others in the $2,000 and under catagory. Notably the Bryston 9B-ST (or the Lexicons of the same heritage)Integra Research RDA-7, and others. Will these amps sound better even though they are rated at a lower wattage ? Any suggestions as to what would clearly beat the Sherbourn, or would the improvement from this level be negligible ?