Probably the brand new Canon EOS 5D Mark IV is the hot potato that everyone is talking these days. And I've seen so many disappointed voices, especially from videographers. I understand that 5D Mark II was a deal breaker for them and they are so hoped that the fourth iteration would be somewhat close to Sony A7rII or A7sII.
I am not a videographer. So I don't care much about the video side of functions on this camera. I always wished they should release two models and one for more photographers oriented and the other one for more videographers oriented. So person like me can choose more photo dedicated 5D and probably okay with HD 30p is good enough or even no video function at all.
Canon has their cinema line of cameras and they might not want to interrupt its sales from other side of lines. But blaming on Canon being safe play and the amount of new stuff they bring to our table is not enough are over judged in my opinion. 5D Mark IV will be a solid and powerful tool for many photographers and videographers.
Sony too often releases new cameras and none of them seem to me well cooked. RX 1R II is without 5 AXIS IBIS. And it is way more expensive than what people were hoping for. They sure is up on their sensor technology. But they still didn't figure it out how to make their cameras to be not overheated or good battery life. I believe second generation A7 cameras are amazingly good. But still to me it is not good enough me to jump from my canon 5D Mark III to their side. I wish A7RII was bigger and bigger grip and better battery life. And wish it has a touch screen. Also hope the IBIS is better than what they are selling for(of course it is still better than none and it is useful when it comes to low shutter speeds). And recent complaints about their pro services are also my concern. If it is less than $1,000, I might cope with that. But it is my working tool and when it has issues then I want the company to take care of it as much as it worth.
5D Mark IV will be always bigger than the A7s. And heavier. Maybe the video functions are not as good as Sonys. But I am still not ready to jump on to Sony. I still like my 5D. It is reliable. It feels like a tank and feels good on my hands too. The lenses I own are pretty good, so I don't need any adapters to use(except EOS M3). I still think prefer Canon's AF is way more than the Sony's. That is why I might move on to 5D Mark IV instead of the Sony Alphas. Can't wait until I try the brand new 5D Mark IV with my own hands.