My experience is very similar to Ozzy's. I have had lots of power conditioners - Monster, PS Audio, Shunyata, Richard Gray, audience (with and without teflon capacitors) - and at each price point, audience proved to be the best. Shunyata was also very good, but I definitely prefer audience.
I started with the Monster Cable 3500, then moved up to their 7000 (which was much better - I soon realized that the 3500 was very bad sounding and the 7000 was less degrading to the sound, but I had to go in a different direction. I tried the Richard Gray unit (he left monster to make these conditioners the way he had originally intended). This was a big improvement over the monsters, but now I was interested to see what else was out there.
I bought the PS Audio Power Port Premier next. Because of the different designs of these different conditioners, it is not always easy to compare them. One might sound better with digital sources (because of its filtration), but it might also make vinyl sound lifeless. Overall, the PS Audio was very good, but it definitely did not help with amplifiers. Next I tried audience, as I am a big fan of their cables and disc cleaner.
I bought the audience aR2p and connected it to a Wiremold powerstrip, and the amount of improvement/dollar was outstanding. All components sounded better than any of the other conditioners. Then I tried a Shunyata Hydra-2 and found it was a bit better with my digital gear, but my analog sources and amplifiers sounded better with the aR2p/wiremold, so I kept all 3.
After using the Hydra-2 for a while, I upgraded by CD Player and found that the Hydra-2 was no longer better than the aR2p on my digital gear.I decided to sell the audience aR2p and Shunyata Hydra-2 and move up to the aR2p-TO (with Teflon capacitors). This was the biggest power conditioner improvement I had made! I saved up and sold the aR2p-TO and moved up to the aR6-T. The isolation between outlets made another big improvement, so I was content with my power for quite a while.
As my system expanded, I moved up to the aR12-T and am very happy with my AC. FYI, I have found that JPS Labs makes the best power cables for my system, and I have tried even more brands of power cables!
Happy listening!
Dave