Does anyone know any "decent" clubs that would hopefully have Trance playing? Even if it's just a club which may have a monthly party or something, I am going with my fience' down there for the holidays again but never found anything last year.

it's a little late but you can try Playa del Carmen, much better electronic nightlife. But very little trance it's mostly house and techno.

there's also this in january http://www.thebpmconference.com/ i've been there this past 2 editions and they were great.