I have had a Nikkor 85 f/1.4 for about 20 years now, I have used it extensively and know it's limitations and strengths.
I have also used the new Zeiss 85 f/1.4 for a couple of days in tandem with my Nikkor a short time after it was available in this country. I didn't know about the Vivitar Series 1 85 f/1.4 at all, something new to look at one day
My take of the Nikkor and Zeiss is that they are comparable to Hasselblad and Mamiya RB/RZ lenses.
The Mamiya lenses are slightly contrastier, a poofteenth to be precise, over the Hasselblad lenses. This was noticeable in a busy studio/lab environment I once worked in. As you walked up to the vertical lightbox to take another four 120 transparency films down, you could pick the different lenses by the contrast of the film.
The 85 Zeiss lens was very interesting, seemed to be almost identical in feel and look through the viewfinder. As for contrast, yep, pretty much a Hasselblad and Mamiya difference, but seemed less than I remembered from 20 years ago when in the lab/studio.
There was one real difference between the Nikkor and Zeiss, the Zeiss has ½ click stops. I have used Nikkor lenses almost forever, but I do have a couple of lenses that are not Nikkors. One that I use a lot is the Sigma Super Wide II 24 f/2.8 it has ½ stop clicks and I have to admit I love them, but somehow I seem to get by with all of my Nikkor lenses doing ½ stop guesstimates by feel and in the viewfinder finding.
If ½ stops are important to you then this could be a deciding feature.
I distinctly remember that both lenses focused the same way, this is important to me, maybe less to other people.
If you are going to use either of these lenses wide open, make sure you can focus precisely, depth of focus is really minimal. Also if using them wide open, you need to have the quite largish lens hood attached, they both flare.
From F4 to F5.6½ is the sweet spot of the Nikkor, really sweet.
The Nikkor worked slightly better at close focus, I'm not too sure why, but I have just come from my darkroom after viewing the negatives on the light box. The Zeiss seemed to work beautifully from about 1½ to 2 metres from the camera. The Nikkor works quite well down to 1 metre. Both lenses work equally well with landscape type stuff or where the object is greater that 3 metres or more away.
I tested both lenses on a pair of F3 HP cameras side by side on solid tripods. In both cases I used either the WLF or the DW4 both of which have a 6x magnification system built in for the close up and long range landscape testing. Effectively the only difference I could tell was the closer focusing ability of the Nikkor.
In short either would be my choice, your call.
If you find these too expensive then perhaps you could consider the so called lesser lenses. I once entertained the Nikkor 85 f/2 as a possible addition. Nice lens, but it is soft compared to the Nikkor 85 f/1.4. The 85 f/2 required 5.6 before it worked for me.
I'm not so sure about the Vivitar stuff being as good as either the Nikkor or Zeiss flagship models. Many years ago I was on the lookout for a 180 lens. I eagerly awaited the release of the Vivitar 180 f/2.8, nice lens but when it was put alongside the Nikkor 180 f/2.8 with identical cameras and on sturdy tripods, you could literally see the slight softness wide open compared to the Nikkor.
This was at a camera show where I had convinced the Nikon and Vivitar people to do a straight side by side comparison. The Vivitar was literally ½ the price of the Nikkor, so it did appear that you payed for what you got. I bought the Nikkor and have never looked back.
Mick.