Both are great schools. Its pretty much a toss up between the two. I'd say the only convincing reasons to choose one school definitively over the other are based on subjective grounds that vary from person to person (i.e. location, proximity to home, etc).
Baylor has the TMC, but as much as the students there hyped it up I'm not so sure that it gives you a huge clinical advantage as some would say.
Baylor has a condensed curriculum which some people like, but again thats really a subjective criteria and lots of people dont like it either.
I'd say the cities they are located in are roughly equal. Neither Houston nor St Louis compares to NY, Chicago, LA, etc. St. Louis is a lot less humid and milder in general than Houston. In the immediate neighborhoods, I'd say Washu has the edge, but its pretty close. Neither school is located in a bad environment.
I'm choosing WashU because they gave me a full scholarship. If I was offered a full scholarship to Baylor, its very possible I might have gone there. You could ask 100 people about the comparison between the schools and possibly have a 50/50 split on opinions.