What I am about to say is based on my personal research (I was considering a residential investment at one time and I have some legal training) and anecdotal evidence from friends on the island. It's important to note those qualifications because I don't want to give a false impression.
I decided against buying mostly I didn't think it would be a good investment (currency fluctuations, interest rates, a construction pace that apparently outstrips any reasonable demand, and the relatively low rental costs discouraged me) and because I couldn't secure title insurance to my satisfaction. That, along with what seemed to me to be a considerable number of horror stories involving lawyers leaves me happy with my decision, for now. My favorite hard luck story was one that involved a Spanish colonial land grant.