This has been discussed a few times here...
I think the general consensus is that both schools offer great opportunities in both fields. I have heard Duke's MC placements tend to be in the Atlanta offices, but other than that I don't think you will find much difference. Both are tremendous schools, and I certainly wouldn't consider either a safety with how tough it is going to be in the coming year (unless you are a super star).
One last thing to consider is that Michigan has one of the largest, if not the largest, alumni base in the world. This, coupled with the fact that Duke's program is younger (founded only in 1976ish), may mean Michigan is a slightly better brand name, but I will let someone with international experience speak to the truth of that.
Either way, best of luck, and here are two threads that discuss the Fuqua/Ross comparison, one from here, and one from BW.
BW -
https://forums.businessweek.com/n/pfx/fo ... &tid=71396Here -
https://gmatclub.com/forum/103-t43385~Sam