Tough question!
My choices were based on general perception, rankings and other people's advice.
I started narrowing down the schools on the following basis-
1) Location
2) Reputation
3) My chances of getting admitted
4) How they marketed themselves... some schools made me more at home than others.
I realize it is the least desirable way to choose schools, but given the time constraints it was the best I could do. I will get some time in the middle of Jan and the end of Feb to schedule my visits, but that does not really serve my purpose. It is more like trying to put out a fire after it has started, instead of preventing the fire in the first place.
But on the other hand i do question to some degree the extent of usefulness of these one day visits. 'A day in Rome, does not a Roman make'.
Can candidates trully find out if they are going to like an environment that they are going to spend two years of their lives in, based on a single eight hour visit or a single class?