Yep, I'm sort of an example of "do as I say, not as I do", although so far things have worked out very well for me. If you want the long version PM me, but basically I am an older, non-traditional student coming from a difficult undergraduate degree/previous career that started over from scratch in medicine. On top of that, I received terrible advice from my (non-medical) advisor that basically hobbled me when it came time for application cycles for USMD programs, and then I made absolutely terrible decisions when it came time for applications. Finally, when it came down to deciding between Caribbean MD/USDO, I felt constrained because I have interest in pursuing some international relief work in a handful of countries which aren't DO-friendly, so I ultimately chose the Caribbean route. If I knew then what I know now, I'm pretty convinced I could have snuck my way into a USMD, but I felt like I was running out of time and I was impatient, and also the applications landscape has changed significantly since I applied. So I went to SGU.
Despite feeling like I've overcome some pretty significant obstacles thus far, the biggest one (residency) is still ahead of me. So I'm not sure I can adequately answer your second question. I was very well-prepared for the Step 1 exam -- SGU does a fine job of that, and so do Ross and AUA from anecdotal evidence. They'll supply the information and resources if you've got the diligence and willpower to utilize them. I'm studying for Step 2 CS/CK now, and it seems overwhelming but I think that's pretty normal. I feel like I've made good connections with my clinical preceptors thus far, and they've all had positive things to say about the SGU program, so I'm optimistic about that, but that may be more a product of my geographical location. If you are willing to make some sacrifices about where you practice, what programs you're interested in, and what area of medicine you want to practice, SGU can deliver a fantastic education. That's why being informed before you apply is so critical. For certain destinations, a Caribbean MD can be a viable and even enjoyable journey, but for others it can be an arduous or impossible barrier. Have a plan, have a backup plan, and have a backup-backup plan.
As always, if you have specific questions feel free to PM me. Good luck!