I think the 70-200/4 is close to perfect as it is; it is sharp wide open, has very pleasing rendition, maintains its focal length quite well upon close focus, and focuses down to 1:4 magnification. It is quite well built (for a lens of this class), the focusing and zooming rings operate smoothly. Its VR implementation gives a steady image and is effective.
If I can criticize the 70-200/4 a bit, in my experience the image softens a bit upon close focus. Also I noticed the VR malfunctioned in cold winter weather when I was doing some hand held landscape shots; I realized I needed to switch to a tripod. Perhaps the VR mechanism froze inside.
It is a recent lens and of the three f/4 zooms (16-35, 24-120, and 70-200) it is easily the best in image quality. Its relatilvely small size makes it much less consipicuous than the f/2.8 variants. Eventually, of course, most lenses may be updated, but this lens cannot really afford a significant price hike (FL) if it is to remain a high quality relatively affordable telephoto for the widest possible audience. I think improving the 24-120/4 and 16-35/4 to a similar image quality standard should more more important than updating the 70-200/4. Perhaps a 24-70/4 is something that Nikon could consider.
The 70-200/2.8 E seems to bring the more steady VR of the f/4 version into the f/2.8 world. I have tested the f/2.8 E now a bit and find the VR performance to be very good. The autofocus is almost instantaneous even in dim light however, sometimes the AF won't even start if there isn't sufficient contrast apparently. I was surprised that it wouldn't focus on my laptop screen where there was black text on white background. Only by moving the focus sensor on the edge of the laptop display did it initiate autofocus. This was with a D810. Anyway, it is understandable that sometimes AF won't work.Mostly the AF seems to work perfectly in indoor environments and I didn't notice any immediate need to apply fine tuning on either of my cameras.
I find the custom buttons on the lens to be very easy to use on this lens, with some of my fingers around the zoom ring, I could easily use my thumb to activate the lens button and switch to 21-point area AF (I normally keep the camera on single point focus but for some subjects I would like easy access to an area around the selected points). I really like it that I can use my left hand to perform some functions instead of having to find the buttons on the right hand side (on the D5, there is a column of buttons on the front side, Pv, Fn1, Fn2, but I don't find locating the right button so easy especially when swiching between horizontal and vertical orientations). So I press the lens button to switch area mode temporarily and AF-ON with my thumb to activate AF. I have had these lens buttons on the 200/2 but there were not so many useful functions available to program them to carry out with older cameras, and with just one lens with the buttons, I didn't develop the routine of using them. The 70-200/2.8E's lens buttons probably get enough use that I will start to intuitively reach for them when shooting sports etc. I've usually settled on single point AF most of the time because switching between area modes is too slow. I programmed my Fn1 and Fn2 buttons to reset the focus point to a "default" position which is in the top center part of the frame (for a people photographer this is where the face is most commonly located) and depends on the orientation. I quite find this feature (and the orientation sensitivity) to speed up shooting. If I want to go back to center point I can get that by pressing on one of the multi-selector buttons with my thumb.
Unfortunately weather is very gloomy at the moment so I can't get any outdoor experience with the new lens. I think during the weekend we will get some fresh snow so I can try doing some landscapes and maybe test the autofocus capabilities in an outdoor environment.
I noticed that the RRS foot for the 70-200G and G II fits but is not a perfect match for the new lens as the length and height of the dovetail are different and I noticed that RRS is working on a new foot for the E version of the lens, but it is not yet available. For now I will use a QR plate attached to the standard Nikon foot.
I find the weight reduction to be surprisingly noticeable and especially when lifting the camera body with lens attached, one can do it with one hand comfortably. When the tripod foot is in place and is in my left palm, the new position of the zoom ring seems perfect for easy access, but without the foot, I appear to instinctively reach for the focus ring. I guess 15+ years of using this type of zooms with the rear ring being the zoom ring means I need to learn a new habit.
I don't really want to keep the foot on the lens when I'm hand holding it especially with a QR plate it would be uncomfortable. I often see people shoot like this though, with their palm holding the foot. I think the best way to hold the new lens (without foot) is probably to hold my thumb and ring finger around the gap between the two rings and operate the zoom ring as needed. The zoom ring is very light to operate and gives an even resistance. I guess the main difference here is that with the VR G II version the holding position is such that the weight of the lens and the camera are mostly the responsibility of the left hand, and the right hand just operates the controls on the camera. With the VR E FL version, the right hand holds most of the weight of the camera + lens and the left hand has a minor role, basically operating the zoom ring and the lens buttons, if held in the way I described. If the foot is in place then holding the overall weight of the lens+camera setup can be done using the left hand as in the past. If I take off the foot and let the lens barrel rest on my left hand, this feels at least initially a bit uncomfortable as my left wrist needs to bend too much. Anyway this is just something to get used to, and mostly I think the ergonomics is improved thanks to the reduced weight and less front heavy setup. The left hand has now more functions to operate through the buttons, if the user should choose to take advantage of them.