I have to disagree, if the power supply quality is bad and it fluctuates then the performance of the hardware will be sub par. This is from personal experience in many locations that I lived in, including studios, etc. A 100$ surge preventer/power conditioner will in most cases solve any hum issues and filter out hums. More expensive conditioners will not only filter but try to adjust a stable output to hardware.
Couple things. Read my post again please. I said if your power is bad, then conditioning and especially regeneration are beneficial. Otherwise, it's a waste of money...or atleast very poor value for your money.
Secondly, I've always found cheap power conditioners and especially surge protectors to harm SQ compared to directly plugging into a wall-socket. Once again, assuming you have decent power in the area to begin with.