It's obvious that your "extensive research" wasn't very extensive if you think GMU offers the best opportunities to it's graduates, especially if you are using national placement as a key consideration. You are probably just looking at their at graduation employment rate, which can be easily manipulated. GMU places 88% of it's students in the South Atlantic area. That's because no one outside the South Atlantic area has heard of GMU. It has virtually no national recognition.
Vanderbilt, on the other hand, has a comperable at-graduation employment rate as GMU, the same average average starting salary, and places no more than ~30% of it's graduates in any given market area. While Tulane has a lower at-graduation employment rate, it has the same average starting salary as GMU and also places no more than ~30% of it's graduates in any give market area.
I've done extensive research on Tulane. In particular how it compares to similarly ranked schools (Vandy, Richmond, Miami, William and Mary, American, and GMU).
From what I can tell so far, GMU has the best job opportunities afforded to graduates. Vanderbilt and American would be a close second. I think that both of these school's have gained both a solid local reputation, as well as a good "big law" reputation in the large cities-DC, NYC, etc.
I'd say that Tulane, Miami, and Richmond are all a clear step behind in terms of the national job opportunities in a wide range of fields.
Just my two cents..