Somebody using the handle JeffyPoooh (yes, ‘ooo’) left a comment on The Register that is an only slightly exaggerated summary of the reasons for UPSide:
You’re concerned about your family’s safety. So you get a guard dog. The dog costs a fortune. It immediately poops on the floor. Then it chews off the entire left side of your Bang and Olufson. It bites the postman’s fingers. It then sleeps through an actual burglary. And finally it eats one of your children.
This is the UPS experience: If they’re not preoccupied with smoldering their lead acid batteries, then they’re busy buzzing and arcing. Then they blow an internal fuse on the output, and your Great American Novel is suddenly lost, again, for the third time. Then there’s an actually power failure (Yay!), so they turn on their patented 387 volt offset square wave, and your PC is instantly corrupted. Meanwhile battery acid squirts out onto the ceiling, again. Then, while you’re out trying to buy a replacement PC, the UPS catches fire and burns your house down.
I’d happily pay $800 to not have one.