For us, it's less that I want to run things on more than one cloud at a time. It's that the next time there's a shuffling of the deck-chairs 5 levels above my pay grade and we end up under someone who says "Oceania Web Services is much better than the Eurasia Cloud Platform! We must move everything at once!" it's not a 3 year migration project (by which time, guess what, Eurasia is mysteriously better than Oceania again).