Lenny2 and I thought about buying one until we tested out a Scandinavian Foam Mattress - the Valhalla - by
May & Company. It has the same type of material that a Tempur-Pedic bed has but only as the top layer. The bottom layer is similar to that of a regular mattress, only better quality. We've had it for almost a year and love it.
The set was much less expensive than the Tempur-Pedic and, personally, just as comfortable.