Does power conditioning really matter?

On an 8 foot projector screen you will see differences in picture quality, sharpness, contrast, noise, artifacts etc. when using power conditioners. Reduce the picture to 30 inches and they're not noticeable.

Jamesw20,no advertisement. Look at my feedback and you will see a couple of cords I have used. Go to ebay and find this guy and you will clearly see we live thousands of miles away. I know the guys name is Kevin but that is about it. Also, as stated earlier Isolation transformers or even voltage converter transformers do a great job of cleaning the power without robbing detail. Not audiophile looking at all so they really need a good hiding place.

I have to give Monster their due in that they do a great job as a surge protector. I got the $199 model with "stage II" (never defined what that is) filtering and I think it made a modest improvement in the sound for the components I had. One summer day our power company sent some big surges my way and the Monster shut everything down in my system instantly. The digital readout showed 127 volts coming in. Reset was easy. It has done this one other time. So from a gear protection standpoint it works as promised. Given the converience of about 12 color coded outlets, cable, phone and ethernet connections, it's convenient as well.

When the goal is for more high end sound and the components get much better quality, then it becomes easier to hear the differences from power conditioning. I am a huge fan of Audience power conditioners and the change is dramatic in a higher end system.

IT can.

Depends on the condition of the power to start with.

My experience is that the Monsters, especially for the money, do just fine! They make a quieter background, for better contrast of sound, and a quieter picture in my experience. In fact, I've had lots of different "higher end" conditioners and power-stations in my system, and it's usually system/area dependent, at best! Basically, results vary with this stuff. I've yet to EVER read one review on any conditioner, variac, power supply, whatever, that says "this product is the end-all-be-all, and does EVERYTHING perfect!...er, basically, "greatest line conditioner ever created!", basically. They all do something different. They all seam to offer pluses and minuses (show me ONE REVIEW, where some super well regarded and respected, long time audiophile review expert, has found the Valhala of conditioners! Yeah, the product doesn't exist basically.)
All that to say, not only have I used and do use/recommend the monster conditioners, but my experience is they do add benefits (if for nothing else, a big warranty coverage for your stuff if it gets fried), and better than most for the money overall, for little investment. And still, the ONLY way to find out of something works, is to try some and compare! But, if you don't have the time, I think you'll find the Monster, dollar per dollar, to offer good results, yes. (sold em in 5 audio stores over the years, plus custom, plus my systems).
Actually, I like the cheapo's for basic receiver systems (HTS1000/1100, whatever).