The Nikon R10. Sync Sound and so much more.
Technology changes. All the time. Camera makers concentrate on features and new products in rotation because they can't afford to update all their lines at once. When Canon came out with the 5D mk2 and the DSLR video craze took off Nikon and their sensor supplier were busy kicking the crap out of the rest of the market with amazing high ISO cameras that also blew the doors off all of the competitors in the dynamic range arena. In some areas by as much as two stops! That distracted them from the whole video circus for a while.
There was also the insinuation that Nikon didn't know anything about motion and were engaged in a steep learning curve but as the owner and user of a Nikon R10 Super8 film camera I'm here to tell you that they do understand that market; and very well. The R10 was/is an amazing camera and in the heyday of professional Super8 (yes, it really existed) they created camera and lens combinations that were the envy of the industry.
Now Nikon is roaring back into the video space. The D810 and D750 have a bunch of improvements that plant a flag for them in the firmament of the motion space and, if they keep iterating in the same direction, they'll have some wonderful opportunities to succeed. While Canon got an early start and has been a player in the advanced amateur video markets for years (my first two pro-ish video cameras were the L-1 and L-2 high 8 cameras) they seem to have stalled in the DSLR space just as Nikon changed their focus from mercilessly beating on Canon's sensors to now beating them in the video space.
The critical evaluations of the in-camera codec point to much better files being written to the cards with higher sharpness and detail. And with better image quality than the EOS 5D mk3. Canon fans could (correctly) say, "If you are totally into video you should just get a camera from the Canon Cine line-up ---like a C100 type 2----and get to work. But a lot of us are content to use our DSLRs to do the kinds of video projects that mostly wind up on the web somewhere.
Here's what I've found with the D810. The 24 mbs, 24 fps, high quality files right out of camera are detailed, have very little aliasing and have flesh tones that look great. When you switch to 60 fps the bit rate jumps up to 45 mbs so the quality of the footage is preserved. The "Flat" profile is just right. It preserves a good looking file while flattening out what needs to be flattened out in order to grade well in post production. If you need higher image quality so that you can really beat on a file in post you are able to attach a relatively cheap Atomos Ninja Star digital recorder to the camera via the HDMI port, and get clear, clean, uncompressed 8 bit, 4:2:2 files from the camera. And you can get these files on the exterior recorder while writing regular, compressed files to the memory card inside the camera simultaneously. That gives you instant back-up.
When I compare the D810 to the Panasonic GH4 it's easy to see that the Panasonic has the ability to write much less compressed files to the internal memory card and the ability to do 4K recording. On the flip side the D810 files have much less noise at higher ISOs and the ability to do amazingly narrower depth of field at the same angles of view, compared to the M4:3 camera. There's always a trade off somewhere.
Nikon pretty much dropped the ball on previous camera bodies when it came to producing workable and competent video. I think the D750 and D810s are the shots over the bow that signal Nikon will be a forced to be reckoned with going forward. My one big request would be to enable changing audio levels during recording rather that having to stop, go into a menu, change levels and then start again. My take at the moment is that one could grab any of these cameras and make a really good low budget movie. Scratch that. With an out board digital recorder they could make a good any budget movie.
My experiences so far have been very good. Just thought I'd let you know. Looking into NikonHacker.com right now. The possibilities are endless.