Just because someone graduated with a DO doesn't automatically mean that he or she will automatically be "nicer", "more holistic", "friendlier", "non-cutthroat" yadda yadda yadda whatever you hear about osteopaths. I hate it when people say this, it's NOT categorically true... there are nice people and jerks, MD or DO, and one can't generalize like that about human nature. For all intents and purposes, either degree allows the bearer to do the same thing. However, allopaths have fewer barriers to licensing in some states, have the advantage of no stigma attached to their choice of degree (many residencies still do not interview osteopathic students).
This esoterically different "osteopathic philosophy" is kind of bullcrap, and many DO's I know recognize this and are pissed off at their osteopathic association for perpetuating that "we're special" attitude. Yes, there is osteopathic manipulative medicine, but allopaths can learn this with CME. Otherwise, the treatment and approach to patients is (and should be) fundamentally the same.
The USMLE is *not* the great equalizer unfortunately, since school reputation and MD vs DO still are concerns that matter. For example, when was the last time you saw a DO resident at MGH or BIDMC? I'm sure someone's going to google one for me right now to prove me wrong... but the point is, the representation is largely NOT there from the osteopathic schools at the top medical centers.
The vast vast majority of osteopathic students have some flaw in their application: GPA or MCAT. Some might say a few points of GPA don't matter, but since osteopathic schools recalculate GPA based on most current grade for retaken courses, this can push someone up from, say, an AMCAS 2.9 to an osteopathic 3.5. MCAT scores are by and large lower as well. I'm just pointing out facts. Unfortunately many people in the medical field are well aware of these facts and perhaps lump osteopathic students as "less capable" than allopathic ones. This could explain part of the discrimination. These numbers don't mean a whole lot, since the sort of skills that are required for med school are vastly different from those to succeed on the MCAT and in undergrad. Osteopathic schools are fortunately more forgiving of tarnished records. Isn't it kind of telling that the most vociferous "pro-DO!" voices by and large have the poorer academic records? It's great that osteopathic schools give many people a second chance to become physicians, those candidates who otherwise would not be touched by allopathic schools. The difference really should end there though.
Med school is what you make of it. Every med student's experience at every med school is going to be different. One would have to be really gutsy to choose against an allopathic school solely on the basis of a "disorganized interview" or some other silly reasons I have seen posted here -- students make up med schools, and students largely shape their own medical education, guided by good professors.
If you want the smoothest path to licensure and a decent residency, the choice is pretty obvious. Otherwise, extraneous factors come into play that may affect just a handful of students (maintaining relationships, etc.).