Of course it is better to go to a US school rather than a Caribbean school; that is pointing out the obvious. However, I trust you have already exhausted your US options and because your desire to be an MD is strong, you are willing to go the foreign route. I want to start out by saying that you will hear a lot of negatives on these med school posting boards about pursuing the foreign route. PLEASE take them with a BIG grain of salt. If you attend an established foreign school and you work hard you WILL come back to the USA and you WILL get a residency. Many folks have done it for years and will continue to do so for years to come. With that being said, I will tell you my reasons for chosing SGU.
One of the biggest reasons is that SGU has been around for a long time and has a proven track record for producing solid physicians. This is evidenced by the fact that many SGU grads are able to match into respected residencies and most physicians out there practicing in the USA who know of SGU and it's grads have only good things to say about them. I think that SGU's higher admission standards, compared to other Caribbean schools, indicates that they are concerned with taking in students who have potential to succeed rather than just filling their seats with warm bodies and big checkbooks. I believe this is why SGU has a much lower attrition rate and much higher board scores as compared to other schools. Of course they do take some students with lower stats than their avgs. of 3.4 GPA and 26 MCAT, but usually they accept these students as long as they are willing to participate in their Academic Enhancement Program. This program is designed to help students improve their study/test taking skills. Other tutoring services are also offered from faculty and students for all students. I believe this shows that SGU wants their students to do well and they are willing to do a lot to help ensure your success. This impresses me because it seems that some of the other schools don't give students any support at all, leaving the students feeling like all their school cares about is thier $$$. As for SGU's curriculum, I like the fact that they use problem based learning a lot, and also that their curriculum CLOSELY mirrors that of US schools. The facilities are state of the art and they have full time faculty that know how to prepare students for the USMLE's. As for the USMLE's, we all know how important it is to do well on them to secure a residency back home. SGU has had scores over 90% for part one and over 80% for part two for some time now; much higher than some of the other schools. Sure, these higher scores are probably due to the fact that SGU tends to admit more "solid" students, gradewise, but I also believe it is due to their commitment to help students succeed once they decide to attend SGU. As for clinical affiliations back in the USA, they are all at ACGME accredited institutions. This is important to know since you could have BIG trouble getting licensed if you do clinicals at non ACGME accredited places. I made sure to check with the state licensing board of the state I intend to practice medicine in(as should you) in reference to what they thought about foreign medical schools, etc.. I was told that they closely follow the guidelines of California in regard to granting licensing of MD's from foreign schools. Schools that aren't recognized by CA are "red flagged" and it is MUCH harder for graduates from them to gain licensing in my home state. Luckily, SGU is recognized by CA and well known in my state....they said they have had many SGU grads get licensed with NO problems(WHEW!). As far as living conditions go, I think Grenada is nice enough. It is picturesque and it is not in the hurricane belt. The school has dorms and also a great service to help students find off campus housing. Compared to some other schools, SGU seems like it offers a more "stress free" environment in general and there are lots of clubs to get involved in. SGU does have the largest and most active chapter for foreign students in the AMSA too!
I guess I would have to say that the biggest drawback for SGU has to be the cost of attending. But, at least you can get federal student aid and also other private loans the school uses. These have all been in effect for a while and because the school is so solid, there is no danger of them losing their student loan funding anytime soon.
Sorry this post is so long but there is so much to say about things to consider in choosing the right school! Good luck to you.