I'm just a fourth-year medical student applying in GS, so I'm not the most qualified person to answer this question, but I can pass on what others have advised me.
On the last day of one of my subIs, a pediatric surgery fellow looked me straight in the eyes and said, "If you could be HAPPY in ANY other field, don't go into general surgery. I'm not saying 'as happy,' or 'happier,' but HAPPY, period, in another field, then choose that field." Many other residents/ fellows/ attendings have reiterated his statement. Their rationale is that GS residency is arguably the most grueling, exhausting, life-sucking training program out there, and that it can be a pretty thankless field if you could see yourself happy anywhere else. The GS lifestyle partly explains why the subspecialties - ENT, ortho, uro, etc. - are so competitive. Surgeons in the subs have better hours, fewer complications, a smaller subset of clinical problems they have to address, yet they get to operate & have all the fun in the OR they want. As a GS, you're the one managing the post-op complicatioins for myriad patients with an equally broad array of clinical problems. You're the one called for most surgical emergencies, and for every trauma and questionably acute abdomen. You're consulted up the wazoo by other services on the floors, for chest tubes, lines, wound care.
I've chosen GS because when the peds surg fellow posed the above question to me, my answer was a resounding 'no' - I couldn't be happy doing anything else. I've done rotations with 9-5 schedules and been miserable out of my mind, while on surgery, when I'm working 18 hours daily, I'm exhausted but happy as a clam. I think this field would be much more difficult if you didn't love it.
What year are you in school? If you're having trouble deciding, I'd highly recommend a sub-I in surgery and another one in a field that interests you, and compare the two.