Paumera:
I won't be discouraged about the comments re Ortho - I have seen many, many internal medicine interns and residents put in just as much, if not more, time "in" at the hospital as the surgical specialties. Albeit there are more lifestyle oriented fields of medicine than these two branches and I would suggest you peruse Freida to see what the "average" attending does after residency.
I was once told (by the head of surgery) that one cannot base their choice of field in medicine on the trials and tribulations of the residency - no matter which you choose, it CAN be bruttal (OK, maybe not Derm). He then commented that only if you are a micromanager, your future practice will consume you - However, if you can delegate and are comfortable with your staff (who, incidentally, are competent and have years of clinical knowledge), your workload, and subsequently time commitment, will be significantly reduced. I don't want to get into a debate over who works harder, but I think that your practice is what you make of it.
Go for it.
Moreover, as a somewhat older MSIII, I find that patients are a bit more receptive to a more "mature" doctor (I use this term loosely, as you will find that many, many patients feel their med student is 'their doctor' due to the large amount of time we give them, compared with the time pressured interns/residents/attendings) - Life experience is tantamount to understanding many of the psychosocial issues in medicine, and these transcend every field of medicine - surgical or otherwise.
In short - Yeah, you'll work hard. Yeah, at times you'll wonder what the hell you were thinking. You'll ruminate about leaving your former profession and question if this is right for you. But at the end of the day, I know I could do nothing else and be professionally, personally and even spiritually happy.
You know what you need to do - If it's medicine, drive on.
Airborne