I wouldn't call it "by far" the best. TechReport IMO has taken a similar style of super-duper in-depth reviews. Phoronix is the only review site that does this kind of in-depth review... except from a Linux-slant. (how good are the drivers for various graphics cards. Which CPU offers the best compile times, etc. etc.)

What CNet lacks in depth, it gains in breadth. CNet has far far more reviews of decent quality than any other site I know. In comparison, the few reviews that Anandtech / TechReport do are far far deeper than anything from CNet.

I think overall, I prefer TechReport over Anandtech.