Kevin,
Did you make a decision yet?
I can't speak for the other seminaries mentioned. I know Southern a little and would recommend it. TMS does have dispensational teaching, but anyone who says it's a prevalent portion of the instruction hasn't been here. There are a few of the older profs who hold up the Dispensational banner, but even then it's more of a position of hermeneutics than systematics. Don't get me wrong, it's here, but not shoved down your throat at all. I only have one more class to take before graduating, Theology IV. It deals with eschatology, so I'll know more about how that's handled in a few months. From what I understand the professor is very gracious about it though. We have had a few graduate as post-millennial. There are several of us who are still trying to work through it. It simply isn't a huge issue, contrary to what many think. The focus is clear in the catalog. Languages, hermeneutics, exegesis, exposition, pastoral theology and of course systamatics are all taught as part of the curriculum, but the focus is on exposition and being equipped to that end.
I'm not sure, but I think the reason so many graduate from here as pretrib/premil is because they came here that way. But, as MacArthur has said, it's not an area of division. That's why he loves sharing the platform with men like Sproul.
Hope that helps. Let me know if I can be of any help.
By the way, the beginnings of a new seminary in Florida are taking shape. I think it's supposed to be called The Expositor's Seminary. It will have a similar curriculum as TMS, but will involve more churches. I'm not sure what that will look like, and I just found out about it, but it's worth keeping an eye on. It'll probably be in the Tampa area, but will have satelites in other towns, including one in another state (sorry can't remember which state). That's all I know. Details are sketchy right now.