Sony's 42MP sensor in A7RII is of BSI type, and is superior to the curreent 24MP one in A7II, D610, D750 even in terms of low light noise. The dynamic range of A7RII is a bit narrower than D610/750 at lower ISO, but wider in high ISO, according to DXOmarks.
The new 46MP sensor for the rumored D820 should be of BSI type, and, considering that Nikon designs the camera more for stills than movies, there is hope that D820 performs better than D750.