Most U.S. auto magazines aren't very well written; all of the articles sound the same after awhile (I gave up on Motor Trend for this reason). Sad to say, most of the U.S. niche-area auto magazines are even worse.
Of the U.S. broad-category automotive magazines, Car & Driver is probably the best. Their editorials always make me think; the letters are hysterical. I always thought their editors were knowledgeable, but recently I discovered why: An issue a few months ago described the process of filling some positions at the magazine, and noted that all technical editors are required to have a bachelor's degree in a technical discipline (as I recall, all have engineering degrees) in addition to specific automotive enthusiast background and other requirements. In other words, you've got to be more than just a knowledgeable car-crazy person to apply.
However, almost all U.S. automotive magazines pale in comparison to the Brits. For up-to-date stuff, try BBC Top Gear (sorry, the magazine is better than the offshoot TV show, Fifth Gear).
My all-time favorite automotive magazine of any type (sorry, the Brits win here): Sportscar and Classic. The writing and research are simply phenomenal. There are some cars I now want to own simply because of the article in Sportscar and Classic.
