Having an MDiv, and working on an MA in philosophy, I can say that the MDiv has a definitive time advantage. My current MA program is only 2 years (I'm shooting for 1.5), and I don't know how you could develop an academic friendship with any professors in that span of time. For a two year program, assuming you start taking courses with faculty you would like to write your rec letters immediately (which I wouldn't recommend assuming!), and that professor would have to start writing those letters in the Fall of your second year, you might have taken 1 or two classes with the prof! During my MDiv, I took 30 classes over 3 years, so about 7 of those were with my primary letter writer. That is a definite advantage when it comes to letter writing, because academics WILL NOT leverage their academic reputation on 1-2 courses of experience with a student. That is unless they are "known" for always writing glowing recommendations for anyone with a pulse, in which case the committees reviewing your application will likely look unfavorably upon the letter (have heard stories from faculty on this account). And there are plenty of ways to write a "positive" letter of recommendation while alluding to the fact that he or she only had the student in two classes.
In any case, I say go for the MDiv if only because it gives you more experience. If you've ever been to an academic conference, you'll also know immediately who has homiletics experience and who just went for the MTS
