I have had a number of power conditioners over the years. An Adcom Ace 515, PS Audio P300, Furman Elite 15 PFI and Shunyata Triton to name a few. I only use a power conditioner for my front end. I plug my amp straight into the wall.
I leave all my power conditioners on all the time except the PS Audio. The Furman does sounds better if left on. Shunyata says that it take 3 days for the Triton to sound it's best. Nothing is going to protect you from a lightning strike. If there is a huge power surge it is not going to matter if the conditioner is on or off. Whole house surge protection is the better way to go.
One of the dealers I frequent uses Torus conditioners in his rooms. If I was going to go with that type of active conditioning, the Torus would be my choice.
I got rid of my Furman because I felt it did not isolate noise very well. I had a problem with an intermittent hum in my preamp. After much searching I figured out that the cause was a compact fluorescent bulb in the dining room. I thought the Furman should have cleaned the power a bit better. I never had this problem with the Adcom Ace or PS Audio conditioners.
I got rid of my PS Audio because as I upgrade my front end with a tube preamp and CD player. It just couldn't put out enough power. I thought about a more powerful unit but decided that the Power Plants might just be too limiting.
I now have a Shunyata Triton and I am very happy with it. It is a huge improvement in sound over the Furman Elite.
