In my opinion, there are two basic factors that have to be considered when training tracking. First, what is your objective. In sport, FST is important. In police work, finding the person is the most important. Once your objective has been established, now it's time to pick a method. In my experience picking a method is determined by a couple of factors as well. One, of course, the dog. What works for one, may not work for another. Two, the experience of the trainer. The trainer is first going to use what has been most successfull for them in the past primarily because it's what the trainer feels most comfortable teaching. As a trainer, I've tried to learn as much as I could about all methods. I would hate to lose a good dog, just because I didn't feel comfortable about using a particular method of training. Besides, I think tracking is one of the most fun things you can do with your pants on.
DFrost