I liked the movie a lot, although we agreed it wasn't as good as our favorite Luc Besson movies, La Femme Nikita and The Professional. Jet Li turns in a really good performance—of course a good martial arts performance from him goes without saying, but he did some fairly subtle acting as well. Luc Besson films often have impressive performances from actors who show less of a range in other films. (For example, The Professional co-stars Natalie Portman, whose performance in that film is a lot better than her performances as Padme Amidala in the Star Wars films.)
My first thought on leaving the theater was: "I'm worried this movie won't do well, because it's a hybrid between a martial arts action / gangster flick and a 'chick flick', and I think the martial arts action gangster fans won't like the chick flick parts and the chick flick fans won't like the martial arts action gangster parts."
I like good examples of both genres, but I think I'm pickier about chick flicks. Independently of that, I think the film did a better job on the martial arts action gangster clichés—they seemed to be more deftly handled. (This is a feeling I have in general about Luc Besson movies, but I felt it was more of an issue in this movie than in some others.)
On the other hand, my opinion about the relative merits of the two aspects of the movie may be biased because I'm a big fan of Bob Hoskins, who is really good at playing a gangster. He was really terrifying in this movie. The last film I saw him in was The Long Good Friday, where he plays a similar gangster character, so the roles were talking to each other. (I recommend TLGF but my favorite performance of his remains his role in Mona Lisa.)
Luc Besson films tend to be quite violent. It might sound odd, but I think he does a good job with it, because he treats it like it matters. There's a lot of emotional impact; it's not cartoony; I feel things for the characters who are undergoing it. I don't finish the movie feeling like I've been watching a bunch of actors and stunt people play Doom on the movie screen.
 I know some people think this term is offensive. I don't mean it that way, though, FWIW.