Why everyone wants to go there for med school.
They often don't.
A few generalities for you:
1. Caribbean medical schools are, on average, easier to get into after college when compared to United States allopathic (MD) and osteopathic (DO) institutions. Statistically, many DO programs are slightly easier, though still competitive, compared to many MD programs, such that some people cross-shop and post threads like "should I go to a Caribbean MD or domestic DO program?" which is not a fair question in the first place. I am many years removed from the med school application process, but I don't imagine that's changed too terribly much.
2. Caribbean medical schools sometimes catch a reputation for not being as vested in their interest in the students as United States programs.
3. You will statistically have a harder time getting into more competitive specialties when the residency match rolls around, as well as more competitive programs within any given specialty. You
can do it, but it will be easier for the MD from California with the good board scores and otherwise solid application to get that radiology residency spot than the Caribbean program MD with the good board scores and otherwise solid application.
I have nothing against Caribbean schools. I'm just pointing out what numbers tell me. I have met both solid and mediocre Caribbean-educated physicians.
Google, the NRMP, and this forum have all the information you could ever want.
For context, I'm a US citizen, my MD is from a US allopathic school, and I am currently an emergency medicine resident -- a specialty which is in the middle-leaning-towards-the-right area of the competitiveness curve.
Although, if you're a high school student, easy does it, mate. It'll be fine in the end.