Does anybody have any experience with the Williams-Sonoma professional copper cookware? From the description (and the price) it sounds like tri-ply stainless steel with a copper exterior. Does the copper on this cookware really add any benefit or is it mainly aesthetics? If this is the case it seems like it would be lacking the real benefits of true copper cookware. Am I getting the wrong impression or is this what it seems to be to others too? Thanks.