In my case I have to use one -- one of those old Tice units (badly reviewed sometimes) and the big old "power block" storage device.
I bought the set simply because my house is wired is at 30A, my power-amp if used at higher volumes caused the lights to dim and if we were also using the air conditioner and/or washing machine we'd trip the breakers. The conditioner/power storage set eliminated the problem.
I thought I heard some reduced dynamics when I first plugged them in, but I had just gotten through reading someone who said the Tice units "stangled" the sound of his system. I don't hear it now. I don't know if my initial impression was biased from his comments, I've gotten used it or what. I will say I enjoy the hell out of my system and until I move to a place with more robust wiring, I'm stuck where I am and it's not a bad place at all -- I like being able to "open it up" without fretting about the breakers.