Sony NEX 6 - Canon T4i
The main difference is the Sony uses the mirrorless concept.
That makes for a smaller/lighter camera due to the digital viewfinder.
But smaller also means the battery is also smaller (less shots per charge cycle).
However if you plan to use manual focus, the optical viewfinder on the Canon is better suited for manual focus.
The Sony is twice as fast when in continuous mode (10 shots per second).
For video, the Canon has a microphone jack so that you can use an external microphone.
And you need a better microphone on either camera.