Unless one school has something specific academically that draws you to it, I would base most of your decision on comfort. There aren't many differences in the way History is taught, so I had a lot of leeway to choose based on the school itself. I made my decision based mostly on the campus environment. When I visited the three schools I was considering, I went with the one that was
A) The prettiest (actually a legitimate criteria for me)
B) The best tour/information provided
C) The best interaction I had with current students.

A lot of the decision can be boiled down to feeling. Pick some criteria to use to help, but if one institution feels right to you, don't ignore that. That's probably the best advice I can give.