I posted in the Allo forum in response to your other Duke question, but I think this one is a bit different so I figured I'd reply here as well, with a different focus to my response. I'm currently a 3rd year at Duke, working on a master's degree. Having been through the basic science curriculum and already taken Step 1, here's my two cents.
First off, I was NOT a science major in college. I took mostly humanities courses and got my BA in a humanities field. I literally only took what few science courses I needed in order to apply for medical school, plus biochemistry pass/fail during my senior year because Duke said it was "highly recommended." That said, I found first year to be VERY reasonable. And this isn't because I'm some sort of braniac...I didn't get honors in any basic science courses during first year, and given my second year performance I'm probably now somewhere in the mid to lower top half of the class (in other words, a pretty average Duke student). The whole first block (genetics, cell bio, and biochem) was actually a bit repetitive since I'd taken a genetics course and a biochem course in college, and this whole block is now completely pass/fail, to help minimize the inequalities students have in their backgrounds when entering medical school. After that, things of course get busier, as you start anatomy, physiology and microanatomy. I found this block to be the most strenuous of the year, but still manageable. If you go to all the classes and labs, you might be there from 8-4 or 5 many days of the week during this block, but this is a big "if," as many students choose not to attend all labs/lectures in order to better manage their time. In any case though, spending this much time in class is not at all unlike what I've heard from friends at other top med schools...no matter where you are you're going to work hard and have long days, but that doesn't make it unmanageable. I certainly didn't study at home every night, and I always went out on weekends. Some of my classmates literally NEVER studied except for their cramming the weekend before exams, whereas others studied more regularly but less intensely throughout. In any case, we had TONS of class parties, events, gatherings, etc., and they were always very well attended (at least half of the class would regularly show up!). Clearly, we had time to socialize, have relationships, have hobbies, exercise...whatever it is we wanted to do we were able to do it and make it work. I even had a classmate who taught for Kaplan during first year to make some extra cash. It's really not all that bad of a year, and once it's over you never have to sit in class like that again!!! I hope this helps assuage your fears about the first year.
As I said in my other post, the Duke first year is NOT TWO YEARS SQUEEZED INTO ONE! I don't know why everyone always thinks this...the admissions folks and many Duke students really go out of their way to try to dispose of this misconception, but somehow it always gets propagated. Like I said in my other post, we simply don't cover everything other schools cover, and we have a very good reason for doing it this way. But don't take my word for it...just look at Duke's match list and board scores, you'll see how well it really works!!! It's pretty jaw-dropping to see the unbelievable matches Duke students got last year. I can't wait to see the new list, which should come out in about a month or so. If you're interested in seeing the 2004 list though, it's available here:
http://www.registrar.duke.edu/bulletins/Medicine/
(Just click the button that says "doctor of medicine," and the list will be in the last few pages of this enormous PDF document (pgs 127-130)).
As to your concerns about competitiveness, I've been pleasantly surprised at the willingness of my classmates to collaborate, share notes, and help each other out. During first year some of my classmates would regularly e-mail their spectacular, typed notes to the whole class! And we hung out together quite a bit too. It was pretty typical to find 20-30 members of my class out together in Chapel Hill on a Friday or Saturday night throughout first year, and I've heard that the class after us is even more close knit. After time of course certain groups developed, as people naturally gravitate towards others like them, but overall I've been impressed with the lack of competitiveness among my classmates. Sure, there's always one or two "bad apples," and I can think of a few offhand, but they're BY FAR the exeception rather than the rule, and they certainly don't ruin things for the rest of us. We just ignore and make fun of them!
In all seriousness though, in talking to friends at other top schools I've been told that this degree of collaboration is quite unusual. But it makes sense to me, as Duke really goes out of its way during the admissions process to choose people who they feel will really contribute to the Duke community and to the class. Once you get an interview it's not about MCAT scores and GPA's anymore...it's about who you are as a person, what's important to you, and how your presence might contribute to Duke's incoming class.