Okay, I guess I should comment on this series, as I have just blustered through the four currently available books in this seven book series: It's not really deep, but it is very engaging. And there are many twists that develop as the series moves along, which is, perhaps, why _Crane_ (number four) receives higher marks than the others.
Details regarding the actual movements of martial arts are quite good (although for me, a bit much---I just want to know what else is going to happen), and quite informative (for me, an ignoramus in regards to the different fighting styles). I am personally tickled to have the story move on to Kaifeng (I've been there!), and make historical references.
I am puzzled by the mixing of Cantonese and Mandarin naming (I know, it is part of the plot, but gets me wondering about a broader history of martial arts in China.... and I don't think I really want to go into that line of inquiry right now, so someone just tell me).
Finally, I have enjoyed seeing how the author's biography has evolved over the four books. Pretty neat (check it out).