i'm not a med student yet, but i'm faced with a similar decision.
while i agree with souljah's p.o.v, and, let's face it, i agree with just about everything souljah says since he's probably the wisest and least full of BS person on SDN, i think that there are some other things you might want to think about.
is the difference between the school happy vs. unhappy, or happy vs. happier? because while it would not be good to go to a school you're sure you'd be unhappy at, is it really all that important to be at the place you think you'll be happiest? is it really possible to fully know that you'll be more at home at one place than another?
for example, you might have gotten along really well with current students at a school. but who's to say that your class will be anything like them? or maybe you met a few really great drinking buddies at a second look weekend, but how do you know that once you're in the context of a competitive classroom environment, those same people won't become complete a$$holes?
is the only difference between these schools their ranking? because sometimes rankings, while unreliable, can indicate some real differences in quality. there might be more opportunities, or at least less of an uphill battle to get access to opportunities, at the higher-ranked school . . . more opportunities to do what you think you want to do now, but perhaps more importantly, more opportunities to figure out what's really your true calling.
anyway, this process has made me somewhat of a nihilist, and i've really come to question the notion that the happiness you perceive from visiting a school a handful of times will mean squat once you're actually there.
of course, if your gut is telling you something, go with that! absolutely! but if even your gut is torn in two, as mine is, it might not hurt to question exactly where you got that "at home" feeling from at the one school, and why the other has more "prestige". at least, that's what i'm trying to do. 😉