What are people's experiences of using something marketed as a "wheel wax"? Is this different from any other kind of wax/sealant? I've had a bottle of Mer Wheel Wax for a while (don't know how or why as I never usually buy Mer products), which does not seem particularly impressive or durable. Before I try out another brand of wheel wax, such as Poorboys, would I be just as well to use Megs Ultimate wax on my wheels as well as my paintwork?