OK, the movie doesn't flat-out suck, but it could have been a lot better.
Generally, the action is a mix of "Look how awesome Muay Thai is!" and "Look how awesome a guy doing his own stunts is!" Two things that were shown to us by Sagat in Street Fighter II, and Jackie Chan. And shown better.
A lot of scenes are set up just for the convenience of having something awesome to showcase the stunts, rather than being feeling natural. For example, Ting (the main character) is running down alleys avoiding a gang of thugs. Through which, he jumps tables like they're hurdles, jumps through a cart of baskets (with the baskets peculiarly places like towers with a person-sized gap in the middle), and over a waist-high rack of sharp things.
As I thought to myself "Christ, they might as well have him jump through a flaiming hoop" the movie one-ups me by having him jump through a HOOP OF BARBED WIRE.
And each example of OMG AWESOMENESS~! is replayed in Multi-Angle-Michael-Bay-Explosion-Vision. So in case you just missed Ting sliding under a moving car, they'll show it to you two more times.
To top it off, the subtitles suck. They're more along the lines of Closed Captioning for the Hearing Impaired, rather than a simple subtitle job. Music's playing? Get ready for [Music playing] followed by [Music continues] every five seconds. Lyrics kicking in? [Singing] Someone gets punched, but you don't see it happening? [Punches]. Someone hurt? [Groans] Someone coughing? [Coughing] Someone speaking English? [English] I am NOT making these up.
And when it comes to actually translating the Thai language, it's hit or miss. [Shouting in Thai] [Indecipherable Thai] or just plain [Thai] will pop up more often than they should. While this is usually done in regard to background noise, some of the language can be distinctly heard and should be translated. OR NOT FUCKING POINTED OUT IN THE FIRST PLACE. [Shouting in English]
So, if you were really interested in this movie (possibly because a certain webmaster made an earlier thread saying how JAWESOME it was), I'd suggest a rental.
I'm sounding a lot angrier at this movie than I really am. A lot of little things are pissing me off, but overall the movie is fun to watch. It's just a lot of flash and little content.