The Canon 6D Mark II is decent in terms of viewfinder and LCD performance, but nothing special. The 5D Mark IV, on the other hand, is firmly a professional camera and it has a viewfinder and LCD to go with that designation. On the 6D Mark II, you get a standard 3” rear LCD, with 1040K dots.
Plus, the Canon 11-24mm F/4 is a really great lens and not something available from the other systems. But, I have to be honest, I would have loved to have some extra dynamic range from time to time, and my Canon 5D Mark II, and then Mark III, have definitely fallen short of the competitors in this category.
Similarly, Bill Claff has measured the engineering dynamic range of the 6D Mark II to be 11.1 EV at the pixel level, at 12.7 at ISO 160 for the 5D Mark IV (its highest dynamic range). So those 6D II and 5D IV figures are off by a stop.
Canon EOS R vs Canon EOS 6D Mark II vs Canon EOS 5D Mark IV (Dynamic Range) 11.9 Evs. Sports (Low-Light ISO) 2862 ISO. Canon EOS 5D Mark IV.Canon EOS 5D Mark IV vs Canon EOS 5D Mark II COMPARISON SELECTION (3 selected items max.) Landscape (Dynamic Range) 11.9 Evs. Sports (Low-Light ISO) 1815 ISO