Good question.
1) I want to work overseas primarily when I am finished with residency, whether through MSF or another organization is yet to be determined. The way I see it, general surgeons are very well equipped to deal with almost any area of medicine. General surgeons are proficient in trauma, minor/major operations, can manage floor patients and deal with those associated issues, and can take care of ICU patients (not a lot of that going on in the jungle, but the more knowledge/skill you have, the better, right?) I know that I won't be doing AAA repairs or whipples overseas, but I think the confidence and skill set that comes from the well-rounded education that surgery residents receive will serve me well. I do think that there is a role for ENT's overseas, but in my best estimation, the training that general surgery affords is more appropriate.
2) There's stuff that general surgeons do that ENT's don't, and it's the stuff I really really like, such as critical care and trauma. My favorite part of my surgery rotation was the trauma/critical care month I did. I really dig that stuff (and if anyone asks, no, it wasn't the blood/guts and glory trauma that turned me on about it. I really liked rounding on the SICU patients and discussing their physiology and management with the resident. The exciting trauma stuff is cool, but it's so relatively infrequent, especially at my institution, that it wasn't the clincher) and I wouldn't be trained in it or get to do it as an ENT.
3) Chicks.
4) I think I liked ENT too much for the wrong reason. Lifestyle. I say "too much" because I don't think there's anything wrong at all with considering it when making your specialty decision, and you'd be short-sighted not to. However, when people asked me why I liked ENT, it was always the first thing that came into my mind. The actual clinical practice of ENT was always kind of "meh, that's cool I guess" to me.
Just as an aside, it wasn't my Step 1 score. I'm competitive for either field, but at the end of the day I like general surgery more.
Sorry for the novella. Hope this helps.