Why are there so many doing TKD? Probably because there are alot of dojangs either good or bad. Just like in any MA, there is good and bad instructors, schools. Also, it has gotten more known because of the Olympics.
Taekwondo for me is 90% kicking, 10-20% punching etc. I used to run, do aerobics, but I have never been in such great physical condition, and at 55. (aside from my bad knees which I basically ruined running) I love the spinning kicks, the forms, the breaking, the sparring, and the teaching. I love the fact that when you feel like you are physically just wasted from a 2-3 hr. bb test so far, you can reach deep inside and pull out enough energy to do one more jump back kick to your opponent. I think it is one of the more physically demanding arts and because of it, the cardiovascular advantages are tremendous for health and strength. The high kicking, the repetition and amount of kicking we do offers superior leg strength that can't be experienced unless you practice the way we do. Those that are the most critical of TKD don't really know it. A year or two in the art, does not do it as they are still beginners. I realized a big difference in power, at red and later a year after reaching BB.
I also want to add, that the mental aspects for some are just, or maybe more important. The tenets of TKD: Courtesty, integrity, self-control, indomitable spirit and perseverance. Also in our school the keys to success: Respect, repetition, patience, discipline and humility. All students do papers on these and are expected to work on these values in class and in life outside the dojang. TW