Magazines were the way I learned about bbing to begin with! Without them, I would have had no clue what to do. Bodybuilding is not an objective science -- everyone has their own opinion and their own experience. Different people react differently to things based on genetics. But I am still an avid reader of them in my quest to learn more. I have been training for five years, and I fear that unless I get new ideas, I will plateau. Nobody knows everything, and the magazines can suggest new ideas. You take bits and pieces from what magazine articles say (which aren't the final word), and form your own opinion on it.
Of course, I'm talking about the real fitness magazines, not the pretty boy magazines -- "Men's Exercise", "Exercise for Men", etc., although they have pretty good advice on grooming. "Muscle and Fitness" is my favorite, along with "Muscle Media", "Ironman", and a couple of others. Regarding "Flex": Just like the renowned researchers at the Ivy League university that I attended, being good at something doesn't necessarily mean you can teach it well. Most of the pros that write for "Flex" are terrible writers.
If you haven't picked up a magazine in a while, try it! It's almost as good as reading this board!