Well, No DO vs Carib MD discussion is complete without statistics provided by someone.
Check out the match rate for US MDs, US DOs, and FMGs as a group:
http://www.ecfmg.org/cert/factcard.pdf (would you like to be in a group that averages 50% match rate? maybe it's a bit higher with non-documented outside the match offers, but probably not much higher)
Check out the pass rates for USMLE (a test required for some DOs to match at competitive specialties but not required for licensure):
http://www.usmle.org/Scores_Transcripts/performance/2006.html The data is for 2006, the most recent data. FMGs consistently pass at a lower rate as a group compared to both US MDs and US DOs. You'd imagine that as the Steps increase, so would the passing percentages since the FMGs that fail to pass Step 1 wouldn't sit for Step 2, etc. However, the pass rates are low even all the way to Step 3. DOs, interestingly enough, outperformed MDs on Step 3.
Statistics are statistics, so interpret them as you will. However, as a group, I'd rather be part of the DO group than the FMG group. The odds simply aren't in your favor.