I've been looking at the Sheldon Brown website for a long time. Entertaining also.

Still have the Supreme on the front and the Plus on the back. They really have different profiles with the Supreme looking more rounded and 'balloonish" and 2mm bigger going just by the specs from Schwalbe. Don't know how much the tubes have to do with that.

I am going to try the Schwalbe tubes out for fun, they are expensive but not too bad to try one. I ordered the lightyweight tube which I found out weighs about the same as the Q tube. Not really trying to save weight, just want to check them out. Holding air better would be a plus and I have heard they do that. I'll see..