Sony A7r ii is the low light king, there is a new version due in the next couple of months.
I am not going to be buying another camera with 8bit video, so will be holding out until there are more 10bit options out there. HEVC has a 10bit profile and it will be everywhere because of HDR TV's and phones, but might take a year or two to get popular in cameras.
It's amazing in low-light, but I find the colours are pretty washed out and the image can band pretty bad once you apply post processing to get it looking half decent. That's been my experience with it anyway. Didn't know they have a new model - great to hear.
I am not going to be buying another camera with 8bit video, so will be holding out until there are more 10bit options out there. HEVC has a 10bit profile and it will be everywhere because of HDR TV's and phones, but might take a year or two to get popular in cameras.