I have now been using the D750 for over 6 months so thought it was time for an update on my original Nikon D750 Review.
The first thing to note is that I have stopped using the grip - to me it makes the camera feel clunky and awkward so it has gone. One of the benefits is the smaller form factor so why make it bigger. In daily use the camera has been pretty much perfect for my needs, it is a great wedding camera, perfect for press and PR work and OK for sport. I say OK because there is the buffer issue but I don't really spray and prey or shoot sport at a level where it is an issue. If you earn your money shooting mainly sport this is probably not the camera for you.
I now find myself shooting manual with auto ISO enabled most of the time and this seems to work really well with this body. The ability of the focus system still amazes me both in terms of speed and how it shoots virtually in the dark. The RAW files are very good and the amount of detail that can be pulled from shadows is incredible.
I use the flip screen far more than I ever expected both for overhead shots and low level shooting - I can't imagine ever going back to a fixed screen. The built in WIFI works well although the app is not great. It has on a number of occasions allowed me to submit news images almost live.
My overall assessment of the camera hasn't changed - I like it so much that I now own three. Two that I use daily and one as a back-up or video camera. There are of course a couple of niggles, the first is that sometimes they seem a little slow or unresponsive, not whilst shooting but when reviewing images or sometimes when in the menus. These delays are really just a niggle and not a big issue for me. The other gripe is the fact that the rear display illuminates whenever you change the ISO which seems pretty stupid but again no biggy!