I see the BMCC has already been mentioned a good bit, but just for the guy who thought about upgrading from the mk3 to the c100, I would definitely take a look at this video:
This puts the BMCC in perspective against the mk3, and it literally blows it out of the water. Now, I have nothing against the mk3 as I own one, but for video I would definitely take a closer look at the BMCC over the c100. You could get the BMCC, matte box, shoulder mount, SDD drives, an L lens, larger external display and a follow focus and still have change left over for the same price as just the c100 body. That, my friends, is tempting.
And this is just my opinion, but I'd still rather the Sony FS700 over the c100 from the looks of it. Same price range and the FS700 has a 4k firmware upgrade coming out.
It all honestly boils down to what you want though. People have made beautiful films dealing with the horrid H.264 compression in the 5Dmk2 (and nearly all other DSLRs). If you're serious about making movies, you'll find a way to work with whatever you get.