I like the attempt to compare various power conditioners in a given system, but you have to be careful not to draw any absolute conclusions for your own system.
First, the associated equipment used by the reviewer may be less/more high quality than your existing system. Some PCs help offset deficiencies in the build quality/design of the other equipment and, thus, the results can be very system dependent. In particular, lesser quality power supplies in a component can often see more substantial improvements with the right "conditioner".
Frankly, the reviewer's system in this article is a more "real-world" type, but, compared to many, I can see someone saying it's less than normal reference caliber. Thus, your results could vary if your system is using much higher quality components to begin with.
I'm particularly surprised that the RGPC made such a large improvement in that system -- given that he was using a Musical Fidelity integrated amp. I liked and used Richard Gray's products, but I thought the MF products already have a choke regulated power supply, which is similar to what the RGPC does. I would have suspected a less dramatic effect on MF stuff.
As for the Audio Magic, I understand some people swear by them, but it's hard to figure out such high pricing based on parts. Has anyone cracked these open? There must be some unbelievably expensive stuff under the hood or maybe the value is strictly in the improvements it makes.