If you're really gunning for a specialty like Neurosurgery, being the only school in town is going to help you a lot. Tufts students have more opportunities due to the location, but that means there's more competition, and coming from Case is going to help you a lot more than coming from Tufts. It's definitely not impossible, students match well from Tufts, but it does mean you have to work harder.
But outside of that, Boston is a great city to live in (outside of cost of living, which has started to get a bit insane). If it's going to drive you crazy to live in Cleveland you're probably going to have a much better time in Boston. But I don't know that I would turn down an acceptance at Case, particularly if you are interested in more competitive specialties.