Without previous exp in any area or one like this, it's the same old thing... You're going to have to try some for yourself to really know... if you want to find the truth of things. otherwise, it's all bias and conjecture.
Power conditioners which DO NOT regulate the power or regenerate it, won't aid you with fluctuating incoming power levels. In that case you would look for a voltage regulator... and not merely a power line conditioner or filtering unit.
Some PLCs do both and some only attempt to remove artifacts from the line without providing any stabilization of voltage.
I'm certain this topic will be heavily laden in the archives... but then you won't really know looking therre for the answer.... will you?
On a budget? Look for a Running springs Haley... or some other RSA unit. I found no apparent bandwidth limitations, nor any overt current limitations using mine.
Enjoy!