First off I would ask other people who own at the condo you are considering what are the upsides and downsides of that particular property. Though I don't own, I know people who do, mainly in Cozumel. The gist of their experiences:
1, You always have to come up with the total price to buy - no loans unless there is owner financing.
2. No title insurance (mentioned above). Find a reputable Realtor & a LAWYER. Get references.
3. Don't count on paying your mortgage from rentals.
4. Upkeep can be a real $$ pit - things rust, break and mold in the tropics, quickly.
5. Electricity is horrendously expensive. A friend who leaves her condo in the summer has to keep the AC on so things don't mold.
6. If you need to sell, don't count on selling fast. There are properties that have been for sale for years...
7. A friend who comes to this area for 4 months of the year & inherited money considered buying. "The Dream" , right? After looking at properties & crunching the numbers she realized she could come for the next 20 years, rent the nicest villa possible and spend a fraction of the money she would spend buying. And she had none of the maintenance costs.
8. Hurricanes happen here.
9. Do you speak Spanish?
10. If you have the disposable $ to invest, see yourself visiting a lot, or retiring here it can be a good thing. Obviously there are ex-pats in the area. But first, come down for a few months, RENT, and see if this is for you.