They're not great reheated, but they're pretty darn good cold.

Every time I'm on a trip that takes me near one, on the last/second to last day of my trip, I order a dozen double doubles with onions, and they give them to me in a box. I put that box into a plastic bag and put it in the fridge in the hotel room. When I pack my bags and check out, I put the bag with the box in it into my checked bag and check it at the airport. They make it home just fine. My friends think it's disgusting, but I think cold double doubles are phenomenal.