The last power cut I had, about a year ago, involved a "fuzzing" (of-on-off-on very quickly) for 10 seconds prior to a low voltage (~ 100V) supply for 30 mintes or so, then a complete outage. I can imagine that killing hard drives or power supplies. It destroyed a component in a boiler in a house a few doors down. My APC UPS coped perfectly.
FYI, a microwave can work on around 100V, but just spins very very slowly.
They're worth it for the reassurance. Just for kicks I might try an online UPS when I replace my APC Smart-UPS 1500 - perhaps a Dale E201:
http://www.dale-online.co.uk/product...products_id=33