What AB says is about right as far as I determined over years of subscribing, except maybe the part about lying. I can't say that I saw that (and I know I didn't see the particular example he noted), but questioning their competence is spot-on.
They are not biased by advertising, but they are biased and it comes across. Many of the biases weren't a problem for me, but then they seemed to gain validity. As AB noted, sometimes you can't understand why they picked a particular gun out of a group as best. In one case that I recall, they tested 3 9mm carbines and the least accurate and least reliable was given the highest overall rating because it was an AR15 platform and the others were not. The author was sure that if you could find the right ammo for the gun, it would work as well as the others and so being a platform more familiar to people, it is obviously the best of the three. Never mind that accuracy was poor as was reliability.
Don't waste your money.
"If you look through your scope and see your shoe, aim higher."
-- said to me by my 11 year old daughter before going out for hogs 8/13/2011