The results of these power line conditioners are dependent on the power that YOU have in YOUR room and can have little to amazing results.
That being said you can't overlook the advantages of good power. I am a retailer of RGPC products and more importantly a believer and user.
In my system I have a Substation (240 volts to 120 volts version), (2) 400s, (1) 600s, (1) 1200s, (5) Hightension wires for the amps and the 600s & 1200s. My system is very elaborate. It is really two complete system's as I demo several products for my customers in my home. I am a custom installer.
Here is what I currently have...
1 pair of Vandersteen 3A signatures vertically bi-amped with two Pass Labs X250 amps( one for each speaker) with RGPC Hightension wire power cords and Analysis Plus Silver Oval shotgunned speaker wires and XLR interconnects.
1 Vandersteen VCC-5 center channel powered by one channel from a Theta Dreadnaught II amp with a RGPC Hightension wire power cord and Analysis Plus Silver Oval shotgunned speaker wire and XLR interconnect.
1 pair of Vandersteen VSM Signature surrounds powered by two channels of the Theta Dreadnaught II using Analysis Plus oval 12 shotgunned speaker wires.
Soon to add 1 more pair of the Vandersteen VSM sigs for rear surrounds.
A Theta Compli sending digital out to a Theta Generation VIII DAC/ analog preamp to the Pass X-250's for two channel or a Krell SACD to a Pass Labs X-1 preamp to the Pass amps.
And 1 Vandesteen V2W subwoofer and again using Analysis Plus XLR interconnect for subs.
The Compli also sends digital audio to a Theta Casablanca III with Extreme DAC's for DD/DTS and the Compli sends 6 channels of analog out to a Theta Six shooter for multi-channel SACD/DVD audio all of these XLR/BNC/RCA interconnects are Analysis Plus Silver Oval and or Digital oval wires and Power Oval power cords
For video the Theta Compli sends SDI out to an HD LEEZA which goes to either a Sony VPH 1292 9" CRT projector or out to an InFocus Screen Play 777 3 chip DLP projector or Analysis Plus DVI interconnect.
There is also an Dish network model 6000 hi-def box and a JVC 30K D-VHS VCR both going through the HD Leeza. The power cords for the projectors are Analysis Plus Power Oval 10's.
The room is acoustically treated with ASC tube traps, floor to ceiling, using (28) 4 foot columns of varying sizes 9",11", and 16".
The equipment sits on(2) Stillpoints ESS stands with Stillpoints and the amps and subwoofer are on 1st edition Stillpoints amp stands. Many of these source componates have been treated by me using Stillpionts ERS RFI/EMI blocking material, with phenomenal results I might add.
Everything in this system is powered and conditioned by Richard Gray's Power Company and I can tell you that compared to Monster there is no doubt that the RGPC product is far and away better. It is also not cheap, but hey you get what you pay for.
What you hear are a quieter noise floor thus yielding greater depth and width with far greater focus and detail as well as tighter bass and transients.
What you see are better blacks with less video noise and a deep more 3D image with awesome colors.
Just a side point, all of the other powerline conditioners that I am familiar with have an up-side and a down-side. That is, they do some things right or well but have some issues that bring some bad or undesirable effects too. RGPC is the only product I know of that doesn't hurt your sound or picture (see reveiw in The Absolute Sound).
The best way to evaluate them is to plug them into your system and live with them for about a week then take them out and listen/watch. I am sure you will defiantly miss them and choose to buy them. I also recommend that you use at least (2) 400 at a minimum if you want to get the most noticeable improvement.
As a further point ALL PLASMA displays should have at least (1) 400 on the line as their power supplys are very poorly designed and work much better with RGPC conditioning. Try it you will be amazed!
You will ALWAYS need to recalibate your black levels on your video display as the RGPC line conditioners change this.
If you have any doubts you can try their products for free from any good RGPC dealer so you have nothing to lose.