I got to put my hands on a Nikon D750 with the AF-S Nikkor 24-120 mm f/4G ED VR lens at the local Best Buy today. The D750 is impressive. I found it interesting how Nikon intentionally clusters the focus points near the center in all of their non-professional FX cameras these days. The focus points on the D810 are spread out wider than than the D750. The physical design of the D750 is very nice, would have been nicer to see a professional magnesium body. Nikon will sell quite a lot of the D750. This camera will be a success for Nikon. If you are thinking about upgrading, you should do some real research and ask yourself about how will the new camera you are going to buy will solve whatever problems your current camera can't solve for you. I wouldn't recommend the D750 to a new camera owner. The articulating screen on the D750 seems well made, but it does look like a point of failure to me. So be careful, enough force would probably bend or break the screen from the camera. This was also my first time checking out the 24-120mm f/4 from Nikon, that is a very nice lens.
The photographs were taken with my iPhone 4S and edited in Capture One Pro 7.