I heard that if you don't get admitted to the med. school that you submited an early admission application to, you won't have time to apply to other med. schools since you can't apply to any schools until you get your results back.
-there are no guarantees in this process
-if you don't get in, you'll be behind in the application cycle thus jeopardizing your chances of getting into a single school this year.
-you might have second thoughts after interviewing and visiting your dream school
-you'll be under tremendous pressure to "hit it out of the park" on your first at bat.
The general consensus I've heard is to make sure you're in VERY good contact with the adcom and/or dean before you make this decision. So much that they know you by name before you even apply. They'll often let you know whether or not it's a good idea (wink wink) for you to apply ED to their school.