The SL1's claim to fame is the size.  So if that's a factor for you (d), then you kind of have your answer.  Performance wise they are very similar.  The T3i doesn't have continuous autofocus for video, which you also want.  The T3i actually is highly regarded for its video (compared to Canon dSLRs), however you need to install a 3rd party software called Magic Lantern.  I'm going to assume you don't want to mess with that.  I'd say the SL1 is your camera.