+1.
As for portraits: Yes, the Nikkor 2.8/180 ED is very good. The current AF-D 2.8/180 ED is even a bit better.
And then there is the unique AF-D 2/105 DC. Outstanding lens! One of the best Nikkors Nikon has ever made. I love mine.
And with the outstanding Zeiss Milvus and Otus lenses there are lots of further perfect tools for the F6, as manual focussing works excellent with it.
E.g. for portrait photographers the 2.0/135 APO-Sonnar and the 1.4/85 Planar (the new design in the Milvus line) are a league of its own. Highly recommended.
For those who are interested in buying a new F6 these tests / reviews / sources are very helpful:
1.
http://filmbodies.com/cameras/camera-reviews/nikon-f6-review.html
2.
http://www.nikonf6.net/
3.
https://www.youtube.com/watch?v=m-z3ELw9dSc