You may have already made up your mind on where to go by now, but if you are still interested in hearing about Duke Div., I completed my M.Div. at Duke a couple of years ago. What has been said in previous comments, and specifically what you have said about Duke being a confessional community that is also academically rigorous, is correct. Duke rejects the idea that Christian intellectual credibility requires Christians to be vague or open about their theological commitments. This is not to say that Duke encourages theological arrogance or an unwillingness to listen to others' ideas, but rather is a way of recognizing that common terms are a prerequisite to conversations of all kinds, including Christian conversations. There is plenty of room to disagree within Christianity, but denying that Christ is fully God and fully human, for example, would change the character of discourse such that Christian conversation would no longer be possible, since Christ's divinity and humanity are part of the theological bedrock of Christian discourse. I think of Duke's approach to theology as orthodox eccumenism--a commitment to the ecumenical creeds of Christianity, while also being open to a wide range of differing interpretations and perspectives that are informed by those creeds. Perhaps you already understand all of this, but it is at the core of Duke's approach to theology, and I'd love to talk more, if you'd like!
Also, I was strongly encouraged by faculty at Duke to pursue the M.Div. over the M.T.S., and I can tell you that, at Duke at least, you actually have a bit more room for course specialization in the M.Div. than in the M.T.S. This is because the M.T.S. is a two year degree, and requires many of the same--and I mean literally in the same room at the same time--courses as the M.Div. By the time you have completed the core courses for the M.T.S., there aren't many semesters left to take specialized courses, and you have to take what is being offered right then. With the M.Div., by contrast, being able to take a few electives here and there over the course of three years provided a lot more room for specialization than I would have had if I had done the M.T.S. Of course, the M.T.S. does culminate in a thesis, which is certainly beneficial if you plan to go on to doctoral work. Duke has graphs showing the breakdown of core courses and room for electives for both degrees on the website, so you could look at them that way. And also fyi, my understanding from other students is that you can change from M.Div. to M.T.S. without too much hassle after you have matriculated.