I can honestly say I've never had leftover ribs! But, to re-heat any leftovers I try to use the toaster oven first. If that's a no go for whatever reason it's the real oven, then the gas grill, then the charcoal grill..if all else fails I'll use the microwave, but I must have a gun to my head first. I hate food from the microwave! Except popcorn, that's okay in the microwave.
Nice job on your first ribs! They look nice!