Saying Mexican Music is a little bit like saying British Music. What kind? - traditional (many different types), Pop, Rock, Latin alternative, Mexican Ska, Electronic, Bolero, Cumbia, Opera, Classical, Jazz, Modern etc.
I went to Mexican club in Chicago expecting Latin, Flamenco like music, and found weird polka music that was almost impossible to dance. As for the Flamenco, most people in US listen to "Rumba Flamenca" (Gipsy Kings, Paco de Lucia etc), the least respected kind by Flamenco musicians. Rest of the Flamenco is often pretty boring, at least to me.