Do they teach in Spanish?
I am currently a third year at the University of Puerto Rico so maybe I can help answer a couple of questions. There are currently 4 accredited med schools on the island so if you decide to apply then by all means apply to the three private med schools (Ponce, UCC and San Juan Bautista). UPR is a state school and as such they will mostly accept island residents or those with "strong ties" to the island.
Lectures may be taught in english or in spanish, depending on the particular lecturer's preference. In my school I would say about half are in english and half are in spanish. Now, being accredited by the LCME means that ALL quizzes, lecture notes, handouts, exams and other written material are in english, period. The school is required to do so as part of the accreditation process and because the USMLE is in english. All faculty and all students are perfectly fluent in both english and spanish. One of my current classmates barely spoke a word of spanish when she began (married to a graduate from the school so she met the "strong ties" policy) and now after almost 3 years she is perfectly fluent in spanish also. So dont let that be a deterrent, it can be done, even if you barely speak a word of the language.
Being a mostly spanish speaking island most clinical contact WILL be in spanish. The good news is that clinical contact will be fairly limited and supervised the first two years but by the time third year rolls along you will have had enough exposure and practice to not make it an issue.
USMLE step score are pretty much on par with med schools in the US. As part of an orientation seminar offered to students about to take the USMLE they told us that for the last few years my school has had a passing percentage at or slightly above 90% for all first time USMLE step 1 test takers. Not bad at all. Most people interested in PR are worried that it might affect their chances of landing a "good residency". As far as I can tell that is not the case. I know of graduates who were accepted to Johns Hopkins, Mayo Clinic, Boston General and so forth. Most the most well known and respected programs have had graduates of PR schools in their programs. You can do a search and find out for yourself.
My school in particular has many programs with well known medical institutions from around the US. Every year we have students go to Mayo clinic, MD Anderson and other institutions for research. Two of my classmates were accepted to a joint MD/ PhD program with the Mayo Clinic in Rochester pending USMLE scores. MD Anderson is constructing a huge cancer center right next to the school which will open up more opportunities for research for those that are interested. This year the school has a new Dean, Walter Frontera, who was a chair at Harvard (you can google him if you like). He is currently exploring the possibilty of joint programs and research between both schools, so that is something interesting.
Now in the past there have been certain problems with certain residency directors (mostly small programs in the midwest) who thought that PR graduates were FMG's. Fortunately the LCME has taken steps to avoid this and has sent letters to all accredited residency directors clarifying that PR schools are considered US schools. That was probably around 10 years ago, I havent heard of any recent situations where this might be still happening, although I'm pretty sure it might still be a problem in certain areas of the US, especially where the hispanic population is small or nonexistent.
I am originally from the northeast US (have family here though) so what is my take on the island? The people here are pretty social and nice, there is always something going on somewhere. They party pretty hard down here, even in mid semester. We have a tradition of "celebrating" after each and every exam. Its a pretty safe bet to say that every couple of weeks there will be a group of first and second year med students drunk by a pool somewhere. I still have to get used to beach weather in the middle of December but who am I to complain.
My point in all of this is not to boast or make it better than it is. In the end med school is what you make of it, it can be the best time of your life or the most miserable. For most students it's a combination of both
. Probably the most difficult part is getting used to the local culture, but even that is part of the fun.
If you have any questions feel free to ask. Although I am currently in the middle of studying for the USMLE step 1, I will be more than happy to answer your questions.