Alas, I could not afford a D4 and the size/weight was prohibitive - I did go the alternative route and got a used DF with only 13K shutter count for a very good price. It has the D4/4s sensor ( alas not the AF) but delivers stunning IQ and is a dream to work with as I love the tactile dial setup.
This now works in tandem with my D500 and I agree with Sam, the 24-120 f4 is a stunning lens that delivers great quality images and even on the 500 works as a 36-180mm.