I have to agree with most of Kevins' post content. I also know of another designer who uses SBT when ever he feels it is called for to figure out what he is doing. I use SBT myself when screwing around with tweeks or peripheral gear like power filters or power receptacles, to see if I am fooling myself about what I think I heard. I will mention that the middle class in America, and the amount of disposable income they might have to spend on audio, have disappeared. In other words the middle price sector of the market may be gone leaving the lower cost and very high cost market sectors to try to place a product in.
Scotty