I always use something like that, but just for surge protection and RFI filtering. If that's what is in those, I think it's a good idea. There are more sophisticated power conditioners too, combining UPS with power regulation. But I've seen some products that made unrealistic claims, usually connected with improving sound quality. I thinik legitimate products come in two forms: The barrier strip types, some having surge protection and/or RFI filters and the power conditioners that work like uninterruptable power suplies.