A backup is only useful if you can seamlessly (or at least quickly) switch over to it when needed. Having hours of downtime while you're trying to borrow someone's computer doesn't seem acceptable to me.
Actually it can be done seamlessly - since our softwae is backed up on network srevers we can continue to stream if we either have no computer or lose power temporarily. Our IT dept. is pretty responsive and would be able to replace our computer within a day or two.
