The Q-screen on my 7D shows the selected AF area (ie all points, single point, zone AF, etc) which I find to be very useful. The 5D III Q-screen does not seem to have this, or I have not found a way to enable it. So on the 5D III the only way I can determine the current camera setting is to look through the VF and press the shutter button halfway.
I emailed Canon to suggest they include it in the next firmware update - although I received an acknowledgement of my email I did not get a direct response.
Anyone else think this would be useful? - if so it might help for more people to make the suggestion to Canon.