King Hu Hong Kong Kung Fu [that was a mouthful] is considered the pioneer of the entire genre. A pretty bold title, but is not considered King Hu's best or even one of the best Shaw Brothers films. So it made it in the book only for what it is, and not how good it really is.
With that said, I didn't dislike it, but it is a weak 6/10. I already can't remember much about the film 3 weeks after seeing it, leaving no lasting impression. The just average rating is because it wasn't bad... it wasn't really good but it wasn't bad. Bandits kidnap the governors son and the governor sends his daughter, Golden Swallow [no, not a James Bond character], to rescue him.
Not much else to say, the fight scenes were cutting edge, no one did wire fighting kung fu before this. But they aren't nearly as good as the films 10 years later by the same people.
IMDB Link: http://www.imdb.com/title/tt0059079/