A quick update -
We did check out the areas, drove around a lot, talked to a bunch of locals (just nabbed off the streets), walked as much as we could with one bum ankle between us. Here's my opinion for whatever it is worth -
You folks were right, they're all quite different in character.
Tremont: Maybe it was the drizzle, maybe the weekday afternoon, but the area looked a bit empty and run down. True there were a few nice places here and there, but it wasn't our kind of area and the lack of metro access was a nixer.
Ohio City: Very charming, access to groceries and entertainment looked good, metro access got points. But then I didn't like any of the condos there and I am leery of buying a house for the 2-3 year term.
Downtown: We ended up focusing on this area because of its general liveliness and city feel, and the proximity to metro & entertainment. Some really nice condos in the area. I don't know if we necessarily want to live right on top of the bars and restaurants in the Warehouse Dist (and even on a Friday evening, it was nowhere as crowded as any Baltimore, DC, NYC downtown dists. - kind of wondered about that). But somewhere closeby would be nice - flats, public square, etc. Working on that now.