Strictly for video, Sony is murdering the other two. When stills come into the equation? ehh.. Not so much - mostly due to lack of affordable, good native lens options, and no used-market - of which the other two have saturated for nearly 30 years (Yes, I realize the A-Mount cameras use 30 years worth of the Minolta mount, but does anyone really buy those? kinda sad, actually - if only they were still true-HDSLR's?)
Second place video-wise (and probably photo-wise too), i'd take Nikon. Simply because of the D5300 having 1080p60 and taking a dump on the Canon Rebel bodies that haven't changed in 5 years, the D750 being far superior to the 6D in perhaps every real way (unless you own a bunch of vintage glass that will work on canon and it's not Nikon or Leica mount) and the lens options, at least for the screw-drive lenses, being absolutely way affordable (seriously, sometimes cheaper than their MF-only, AIS counterparts that they borrowed optical designs from.. wtf)
I do realize that you can't change aperture in live-view mode on many of their cameras (less you fork out for the D810 like a pixel-peeping, jackoff)... whatever. Buy their lenses with aperture rings like I did. Problem solved. Their newest G-glass isn't that much better anyway, especially if you're Videoing as often or more often than you Photo, it's a great option (unless you get the D5300, in which case the old D-lenses won't Autofocus.. but hey, you can throw on every nikon lens dating back to 1959 on those, so there's plenty of great vintage options soo woo hoo!)
That all said, Canon is still good for video. You have tons of vintage-lens options - not quite as many as the E-mount sony cameras, but still a very good amount - the AF systems are great, the native lens options are very good, and the market is absolutely saturated with their glass and accessories, so your'e still not going to be paying very much. The 7D2 is actually a fantastic camera for those who do lots of sports stuff like us. Crazy fast burstrate, extra range on the 70-200 lenses (which, with the crop factor, turn into like, a 115-320 or something, which is fucking awesome range), a very solid Autofocus system that covers like, the WHOLE VIEWFINDER, and 1080p60 is pretty nice (not to mention, if it's anything like the OG7D, it's build quality is 2nd to none)
Yes, Omnidata will DXOmark them to death and yap about their new sensors being laughable with their resolution standards that tap out at 2010-era quality (all of which doesn't matter a lick for video...), but they're still great cameras, with good noise performance, easy to learn menu systems, and they have cool stuff like Magic Lantern to get the maximum out of their potential if you don't mind futzing around a little.
Ultimately, I switched from Canon to Nikon, but if I hadn't, i'd still be extremely happy with what I've got, so don't count them out (esp. with the 7D2. That's an awesome camera for an NSer)
As for the other options... Panasonic/Olympus? If you're doing just video, then the GH-whatever's will be great. If your'e doing photography, look into the Olympus OM-D instead. Still very good video quality, but with in-body stabilization that will work on every single lens you slap on it, and faster AF. One could also get a GH, and then an Olympus EP-whatever for photography, as those things are tiny, and pretty excellent - especially with the EVF attachment.
And with Fuji? Go with them if you're really only doing stills, as they're pro-quality stuff for photography. They'll technically do video, but for the price, it's not worth getting into the other stuff on the market.
