Best upgrade from Canon T3i ?
 

My entry camera into DSLR world is the Canon T3i. It's a great starter camera and works great for well lit interview style shoots.

Outside of those controlled shoots I am a true run and gun style Videographer.

Have mounted it to a DSLR shoulder rig (which I rarely prop on my shoulder) and get b-roll at conferences or the roaming cam at live concerts ... ofcourse I do a lot of focusing and adjusting on fly (thanks to magic lantern).

Love the DOF and richness of the footage.

Although I have onboard led light it still struggles in low light and as you guessed it tends to be a little grainy.

Am wondering about the 5D mark3 but not sure how user friendly it is to adjust on fly.

Not dedicated exclusively to Canon ... open to other options.

Budget is around $2300.

Your thoughts ?