I went to a wedding a few weeks ago and the photog was using a D750. (Not bashing Canon but..) "I" wonder why anyone shoots Canon, personally (unless you have a lot invested in Canon glass...) For right now, Nikon and Sony simply are putting the best sensors in their cameras -- Nikon using Sony and Tower Jazz sensors, Sony using errr Sony sensors. You can keep Sony's (I'll spare you my thoughts on Sony cameras). Canon (and -whoa- Leica given their price) are simply lagging behind for now, an not by a little. This leaves Nikon as the only choice almost by default for pro event work. The 750 is a great choice for events. 750? Smaller, lighter, great ergonomics, fabulous sensor, scads of glass old and new to choose from -- and you don't need the extra MRs of the 8XX bodies. Who knows why they had two unrelated photos. A bit odd, yes. But maybe the main guy was a solo act and they used a friend starting out for candids as a second shooter.
BTW -- this is why I bought -two- used D600 bodies. Same output as the 750, and $6-700 on the used market (actually rated slightly higher than 750 on DXO). Used prices depressed due to the (imo) overblown "oil spot" issue. I bypassed the big auction site this time and went with the big NYC camera shops for their return policy in case there's a problem. Best deal in town to get a modern/relevant full frame camera.