I've got no rust on my ceramic coated grates. I do have the @%$)(@&#)-ing rust on my SS cart and the wheel mechanism part fell off mine too. Might give them a call and see if they'll replace them, but it would be a PITA to replace them.
I mean, really? Rusted out wheels on their own cart?!?
In other news, I cooked 3 racks of baby backs last weekend on my XL and still love that darn thing.