I don't personally know but the general consensus seems to be, Canon films better than Nikon. So between a T3i and a T4i.. The T4i is a T3i with a touch screen as far as I can figure out.
A $200 touch screen? I don't think it's worth it as nice as it would be.
This is the Canon Comparison.
http://snapsort.com/compare/Canon-Rebel-T4i-vs-Canon-T3i