Personally, I have found some benefit to power conditioners. Over a power strip. I have a pyle pro power strip, the one with the fancy light show on it as a bonus. In any event, because I am sort of an insane collector and such, I have tons and tons of gear and it is all hooked up. The pyle power strip, was causing ground and other noise to come through my speakers. I had a bunch of fancy Studio analog and PPM meters hooked up to it.
I added a ebtech Xlr isolation unit to the sends on the meter collection and the problem was almost gone....... But when I replaced the Pyle strip with an ART PB 4 by 4 the problem was gone. Some how noise would get to the speakers with just a normal power strip.
I like the conditioners as they fit nicely, stacked with rack mount gear, and I especially like the ones with front panel convenience outlets as I use these a lot. They make it easy for me to change or rearrange gear from time to time, and for a few extra dollars they look so pretty with the rest of your gear. Lets face it... Everyone likes pretty, and NO one wants their high end gear which also is usually very pretty to to muddied up by some cheap power strip etc. Mind you I have not spend more than 150.00 on a power conditioner, as I just like the rack mount strip to look good with my gear and I am willing to pay for that.
For 100 dollars you can buy a whole house unit for extra protection from surges , however there are some issues power strips do in fact solve for people, but in my case you need to be an insane collector with tons of gear all hooked up at once to run into some of these issues. Most with a home theater can do without the conditioner if they do not need extra isolation and plugs. Lots with more gear hooked up like the remote turn on found on conditioners, a well placed feature. Rack lighting is also a nice feature, etc,
Power conditioners do give some UTILITY as they call it in Economics, but not as a stand alone protection device.
A Good amplifier requires a adequate power supply, It does not matter what the amplifier is capable of if the power supply will not provide the power required. Most amplifiers have under rated power supplies. It is up to you to make sure you get the ones that are least under rated if at all.