The only one I've used which didn't noticeably degrade the sound was a Brickwall. Now, I don't use any but, if I were to need another, it would be the audio targeted Brickwall. The price is fair too and NO MOVs which wear out.
Decent power strip
I've been searching the forum to find out if there's a reasonably priced ($100-$200) power strip to use for some headphone gear. The only information I was able to dig up was on DIY project power strips which I'm not interested in. I have 3-4 devices to plug in but only a duplex at this location. Any suggestions would be greatly appreciated.