Few people go this route. It's not the normal path and probably for good reason. The downside of not having other schools see your application until October seems significant for me, and, more importantly, my highly seasoned HPO advisor who places many students at top schools around the country every year flat out told me it was a bad idea that she has never seen work to anyone's advantage in her many years. On the other hand, she has seen this go wrong for applicants who chose to ignore her advice or never spoke with her about it.
I interviewed at my top (in-state) choice Sept 8th and was accepted October 18th (with regular admission). I withdrew from my other choices, but received another acceptance in November anyway. Even if I didn't get my first choice, I had other choices by November with plenty of time for moving, etc. There was no one on SDN accepted to my school before me in the 2006-7 cycle (early decision or otherwise). Thus, it can work out very nicely with regular admission as well.
I spoke to one other person who was doing early decision at my top choice, and he had better stats than I did. I'm not sure if he is an SDNer and if he got in (quite possibly he is not; if he was on SDN, I would have expected him to get in earlier and perhaps let others know). My point is that it is possible to get in early under regular admission as well.
I would check into the particular school in question as to when the first regular acceptances vs early decisions go out.
I think what really left an impression on me is the war stories (not early decision, granted) of people with 38 MCATs and 4.0 GPAs who applied to 3 schools and did not get in anywhere (and had to wait another year). This just isn't a process I would take risks on if I could avoid it. I would go through a lot of last-minute scrambling rather than risk waiting another year or finding out even later than everyone else (because my app was considered later by another school).
Here is the typical advice I see (note -- this is not my UG school):
http://studentservices.tufts.edu/hpa/apphandbook/sectionII.htm
Early Decision
"
A very small number of medical school applicants may consider the early decision option that many medical schools offer. This option allows a student to apply early decision to one (and only one) medical school no later than August 1, 2006 and have an answer by October 1, 2006. Students may not apply to any other medical school until October 1. This option makes sense for those students who have a clear first choice of a medical school AND are strong candidates for that school. You should consult with Carol if you are seriously contemplating an early decision applicatio,
to discuss the risks involved.