Canon 5d Mark III
Panasonic GH4

my vote goes to canon 5dmk2 & 5dmk3

Unfortunately the price of Canon is far more than Sony A7r full frame. The 5D mark 2 is far better for video, a slightly for Raw stills than the mark 3 according to digital photography review. Shame as you can't buy the mark 2 new anymore.

personally, i would go to the store and try them all. reason being, unless someone has actually used and owned the cameras in comparision, everything is a hearsay or relying on reviews which we all know is slanted as well.  the right camera for each of us depends on our own handling and ability to master the equipment and the preference.

i say this because many times, we go into the store saying i will buy this because everyone is carrying one, only to come out of the store buying something else, and never regretting it.
what i do is rent the camera(s) and then strike a deal with the manager of knocking off that rental when i decide which camera and lenses to buy eventually.   

failing that, as not everyone has a store to rent like that, i ask to take the camera out to shoot around with my own mem card (one for each camera, of course) , take the cards  home and study the results.  adding the considerations to how much i like the handling (how the camera feels in my hand, focusing,etc) at the store.

the former method is preferred because you can put it through all the situations you expect to be shooting with that camera (night, motion, ISO pushing, focusing , exposure,etc).

if all fails, seek employment in the pro store on weekends, and then get 2 use the cameras while there. ..which i actually did a thousand years back,   a pro av firm as a product demo rep, i get to bring home whatever equipment i had my eyes on , and when i did buy them, get them at cost through the sales mgr.
u can still do that if u join a store as christmas help,etc.. .


you really cannot depend on whether i like a over b, anymore than u asking me if i prefer to choose car a over car b.   just my own thoughts on this, as i never ends up buying the ones everybody carries 

Biggest problem I see with the Sony A7r & A7s is the lack of a variety of full frame E mount lenses.  At least with a Canon body, there are a wide variety of lens available at many different price points from L glass to affordable options which can be useable for Stock images/video.