I've applied to both unis as well. When i went for a visit I personally felt that I could live in Sheffield for 5+ years while I don't see myself in Leicester. It's just this odd feeling you get. I don't think you should be looking at reputation. I've heard that Sheffield and Leicester are pretty equal - both have excellent teaching. I think it'll come down to seeing yourself live there for 5+ years. A big factor that came into my decision was the student union and the sports. Sheffield is known to have a lot of sports so that's what really helped me decide. Good luck with choosing your uni! I'm sure you won't regret it in the end.