There really aren't that many Mexican movies that make it to the US. It makes me wonder what, exactly, a movie has to do to become a foreign export. Probably it has to do what Y tu mama tambien does, which is offer up good cinematography, an original script, and lots of sex. And there is lots of sex, which progresses in fairly predictable ways with enough interpersonal tension and development to make it interesting.
The director seems to take a cue from Amelie in terms of pausing the action to have a narrator report on situations and outcomes that are tangential to the plot but integral to the emotional thrust of the film. This is an interesting device and works well, but there is a curious (thought obviously intentional) two second pause before each narration, during which the visual progresses without sound. The viewer can get used to it but the first several times it feels like bad editing.
As a movie, the plotline of road trip/friendship/threesome story is entertaining and interesting. Secrets about the characters are revealed at appropriate times and I never felt manipulated by the film. The beginning, filled with attention-altering narrative exposition, makes the film slow to get into but once Julio, Tenoch and Tenoch's older cousin Luisa are on the road, you are right there with them. And while the relationships in the film reach a point you may not have encountered in your own life, there is enough ambivalence to everything to make the film feel real enough to relate to.