I have a friend who has that same Monster line conditioner on his home theater system and he really likes it. His house was built in 1945 and still uses some of the original "aluminum" wiring

. There was still a copper shortage from WWII.
Before he bought the conditioner, even though his wiring was properly grounded to Earth ground, he would experience constant "noise" in his audio and in the video when playing a movie from his old VCR tape collection. After adding the conditioner, no noise at all.
However, we still live in
Tornado Alley so full power outages during severe weather are not uncommon. A good UPS with AVR would deal with that, but simply shutting down before a storm hits works just fine with him.
For the record, I have had some bad experiences with Monster products - specifically their cables (not their electronics). We have seen several (enough to indicate a trend or pattern) of very poor quality construction - particularly when it comes to solder connections. There have been several cases of cold solder joints, blobs of excess solder in the connection, and "
birdcaging". These are defects that could have easily been avoided in the first place with proper training and soldering techniques. But perhaps more importantly, they could have easily been detected with even the most rudimentary "quality assurance" inspections before the cables left the assembly area.
So, especially considering their [outrageous!] prices, I recommend avoiding Monster when looking for cables.