Thanks for the sharing. I did considered the 24-120VR f/4. It is lighter, has extended range and cost $600 less. However, prefer the classic 24-70 f2.8 because of better IQ and lowlight handling. Perhaps others with experience with both lenses may want to give their view. Cheers.
The 24-70 is tack sharp and fast. 24-120 is fast, and in lowlight, with VR, quite a performer. It may be f/4 but it doesn't feel anywhere that pale in comparison to 24-70. Only thing is the sides, at the very corner, it is rather soft, but with all things same, most glasses do give that kind of quality on edges.
In lowlight, both performed equally well, with the 24-70 being faster (naturally). Image output, was great.
Cameras used: D600 x 2
Nikon Lenses used: 24-120 f/4 VR, 24-70 f/2.8
Location: S.E.A Aquarium
Not that I'm a professional reviewer, but just shedding my personal thoughts when I ran through the equipment.
The 24-70 on D600 does slow down, but it's reasonably fast. On the D4, it's whoppingly fast and accurate in lowlight (near total darkness on ISO12,800).
The 24-120 on D600 is acceptable, on D4, it's slightly slower than 24-70.
Image quality is great IMHO from both glasses.