You must be careful what you ask for. The problem with unopposed programs is like what the previous poster mentioned, you are it...for every services...all the time. My system used to have an unopposed program and nearly closed it down before the opposed program merged with it. Not because it was "malignant" but because they were getting abused. They were always violating duty hours of some sort (>16 hours straight, <10 hours between shifts, >80 hours per week, <4 days off per month) and many if not all developed extremely bad habits which nearly got many fired. The attendings would constantly put their unwanted responsibilities off on them. The benefit of an opposed program is that you will get to learn from those IN other fields. This learning can and will help you be a rural physician if that is what you want to do.
On a side note, I find it offensive when you assume that AMG's are better than IMG's or that a program with IMG's is inferior to a program without them. I am born and raised in Dallas, Texas. The only accent I have is the occasional southern draw and am labeled an IMG because I was a white male trying to get into medical school during a recession. My co-fellow was born and raised in Houston, TX and he too is labeled an IMG because he attended medical school in the caribbean. We are about as "American" as they come. IMG does not always mean a foreigner with an accent and different cultural background than yourself. You will find sh#* residents of all sorts where ever you go so don't assume that just because you find an opposed or unopposed program full of AMGs that you are set.
Extremely bad habits that nearly got people fired? Do tell!
BTW, to the OP:
I'm at an opposed program; we used to be unopposed, but our hospital ran into hard times and started to cut services and we've been moved in to the university's main tertiary center with the rest of the residency programs.
I'm getting great training, and I agree that there's something to be said about being able to learn with and from folks who are training in those areas. They're constantly in a learning/teaching mentality. I'd wager that on the whole, the teaching is better that way (though I'm sure it's perfectly adequate specialty teaching at the unopposed places too).
One thing though, the culture I'm sure varies greatly from place to place. I've heard horror stories from one FM forum member about his experience at an opposed program. Mine certainly don't line up with his, but I'm at a different place. All I know is that when we transferred our service to this new place, the other programs were tripping over themselves to bring us on board. We're actually getting more opportunities for procedures here; we're seeing far sicker patients too.
I've taken a rural job and my program has taken it on themselves to get me the opportunities I'll need (not that there's really much I don't get by default). For example, I'm working on doing a trauma surgery elective, CCU, PICU extra ED time etc.
One benefit as I see it is that at my place, since it's at a major tertiary care center, I have immediate access to some serious acuity and pathology that often just isn't handled at most unopposed program hospitals. And while it's not likely that I will be managing most of that stuff at my post-residency job (we're a 20 bed hospital); I will be the ED provider, and the hospitalist (I do have a general surgeon) ill likely be the first to lay eyes on the patients as they come through the door. I'll need to be able to recognize stuff; stabilize it and get it treated or sent out promptly. I honestly feel that I'm getting great training for that.