Really it depends on how you liked the first two. While I haven't seen El Mariachi, I have seen Desperado. And there is a lot lacking in this movie as compared to that one.
The gunfights are more hollywood-ish, with too rapid cuts and not enough prolonged shots for you to get a sense of the action, like in Desperado. The story itself is pretty thin. The backstory itself leaves out a lot of rather (what I though) important or at least interesting information. And what's with the sawed-off shotgun Banderas weilds? Does that thing fire rifled rounds or something? Because it behaves in no way like a normal shotgun. And it sometimes suffers from A-Team syndrome, with an extra round or two in it.
On the plus side, though, there are some of the preformances. Depp does a great job as Sands for most of the movie making him a hell of a character; evil and funny all in one. Too bad his end sucks. (Hard.) Some of the one liners are GREAT!! though. My friend and I doubled up laughing during the scene where the two guards are discussing torture. There are a handful of other good lines throughout.
So really, if you were a big fan of the first two (or even just Desperado) give it one shot. Otherwise, the director has done much better stuff in the past.
-- Jack
Thoughts of a tank owner: . o O(Your SUV is my crumple zone)
-- Panther