My thinking on this one has evolved somewhat. When I was teaching MCAT to undergrads, I always tried to convince borderline candidates to go to DO over Caribbean MD, and I stand by that even now (any US degree is going to be easier to land a residency than a foreign degree, period end of story). I also completely agree that the education is largely identical to the majority of US MD schools (Hopkins > DO, but Hopkins > most MD as well). However, now that I'm applying and interviewing in a competitive subspecialty, I think people need to take a long hard look at whether it's worth going DO and narrowing down your realistic residency choices vs trying again the next year for MD.
Basically, the really competitive specialties have a giant stigma against DO candidates. Right or wrong this is verifiably true. Yes there are DO orthopedists, DO dermatologists, and DO ______. But they are few and far between, and just as it's a somewhat unrealistic idea to go to the Caribbean planning on being number one in your class and matching neurosurg, so too it's somewhat unrealistic to go to a DO school with the same plan (hint, lots of people at your school will have the same plan). Competitive fields like ortho where you're looking at 4+ per resident class may be willing to "take a chance" (actual words of a program director) on a DO student, but smaller fields with 1-4 residents per class are harder pressed to (urology, derm, ENT, plastics, neurosurg, rad-onc, ophtho). Yes you may think that you're all in on primary care now, but people change their minds, especially after actually going and living medicine day-in day-out for 1-2 years in med school, which is something you cannot predict and cannot experience until you're actually in your clinical years of medical school. Either way, why the stigma exists is somewhat outdated, but the fact that it does is indisputable, and it would suck to get bitten in the ass by it.