I'm sure this was a thrilling movie in its day - but look at the year it was released. This is pre-VHS time, so you saw this in the theater or you didn't see it. It must have gained quite a bit of myth about it.
By today's standards it is not only very lacking it its quality of film, but also in its content. There are hundreds of more incisive, thorough, and enlightening titles available than this. If it *is* worth it, it is only because of its vintage/cult status - you can say, "I saw it", when the old-timers start talking about the old days.
A great alternative place to start would be the BBC martial arts documentary mini-series "Mind, Body, and Kick-Ass Moves". You will be a lot more entertained and informed, as compared to this movie here.
Obviously the past cannot compete with the present in many respects, and if it weren't for the past there would be no present, but if you are limited on time or money, I would spend it on something else - you won't be missing much.
