My friend lived there for two years while going to school.
He said it's really laid back, great beaches and night life, cheap/good food, fine women, lots of drugs that are cheap, etc. Then he also said you don't want to be an out of towner and go anywhere other then the tourist areas and around the big cities. You are more or less 100% sure to get robbed and have a good chance of getting killed if you stray from those unless you are with someone who knows the local folks.
If you see Lil Ze, run.