We use Microsoft's current online offering, and we've had both a 25% and a 50% refund in the last year and a half. the refund doesn't even begin to make up for the sales losses and confusion when our dealers can't get their orders through to us.
It's always a good idea to use the cloud to host crucial business systems with no fallback plans in case there are problems. Heck, the cloud is good for anything! Personally, my "waste processing" system is routed through the cloud. Sure that two week outage last month was a bit uncomfortable, but I had considered the ramifications of this design before implementing it, as I'm sure you guys did.