If you want to learn video on DSLRs and the like, there are few better resources than EOSHD. Andrew Reid is extremely knowledgable (it actually frightens me how much he knows) and is excellent as a real pro talking about, often, consumer equipment. He recently did a large test with the A7s against a set of cameras, and he says it's replaced his go-to 5D Mark III with Magic Lantern raw.
Reid compared the BlackMagic Pocket Cinema camera, the Panasonic GH4, the Canon 5D Mark III and the Sony A7s (and even the FS100, A7R and the A6000) against each other in various situations to see how they handled color, highlights, dynamic range and sharpness (including artificial sharpness).
The Sony A7S is the first camera to really beat the Canon 5D Mark III on pretty much every level for both stills and video, especially the latter. The A7R did not have the video quality to topple Canon. The A7S not only topples Canon, it destroys their claim to video quality on DSLRs. Canon’s dated consumer and semi-pro DSLRs are now in serious disarray for video and in some ways stills too (dynamic range and low light for instance). In terms of the video shooter they risk losing the market which gave birth to their pro line of Cinema EOS cameras altogether. I warned them about this 3 years ago and nothing has been done. They have focussed all their efforts on Cinema EOS and completely neglected the lower end video shooter.
Your really should read his full ongoing review. I am presently working on my own review to be published shortly, but I can say that I completely agree with Reid to this point. The A7s is a bit wonky to use at first, but it's by far the most gorgeous video camera of its kind I've used to date. If only it gave me better FPS in 1080.