I hear what you are saying and in fact, I was extremely uneasy buying the first set of Firestones last year. I had not purchased anything but Michelin for my personal vehicles for at least 15 years. The tire store owner that we use gave me the devil when we put the Michelin AT 2's on the '04. 5 last summer and it got worse when I went back to get a set for our Silverado. He talked to me until he was nearly blue in the face to talk me in to the Firestones on the Chevy. He swore to me that since their Ford Explorer Nightmare, that in his opinion, Firestone has the highest quality control of any of the tire brands he carries, and he carries them all. Anyhow, I figured since I was going to be buying from him no matter what brand I chose, and that he was actually trying to talk me in to something less expensive, I'd give it a shot. I am certainly happy I did. I liked the Firestones on the Chevy so much that I put a set on my '07.
Having the AT 2's on the '04 and the Firestones on the '07 makes for an easy comparison. They seem to be as equal in performance and wear so far as they could possibly be. The only difference I can tell you is that the Firestone has a little more agressive of a tread and probably a little more road noise. But, I would argue that the AT 2's ride a little rougher and tend to wonder slightly more. Unless something major happens, or I end up with a huge difference in wear, I simply can't justify going with $235/tire for the AT 2's vs. the $153/tire that I spent on the Firestones.