I have not tried them, as they are mucho expensive.
However, I have talked to a guy that has them and got the spiel from Wade himself on how they perform.
He claims the best thing about them (other than the obvious no flats) is that they hook up way better than any other tire. Apparently they provide a much greater traction foot than any air or mousse filled tire can. I would have to hear the pitch again to be able to go more into detail, but it sounded very logical to me when I heard it first.
I understand that the MX crowd is having a hard time biting off on them, but I think that they are put off by the fact that flats aren't a big concern on the track (usually anywho).
I think that if they do indeed priovide a better area of traction, they may well catch on.
But for now, I have to save my money. For $265 a wheel, a man has to be serious about needing them.
But then, I know guys who spend mucho on fancy spokes! :) (I won't mention any of the names of these blingsters) (grin)