I have an F. It is interesting but nothing to write home to Mom about. But I suspect it was back in 1959.
I have an FM2N. I kind of like it but have only burned one roll of film through it yet so I better withhold judgement.
I have an F6 and I love it. I keep telling myself that the Pentax MZ-S is just as good...but I haven't convince myself yet.
if the F6 is representative of Nikon's pro gear, then IMHO Pentax hasn't caught up to that level yet.
However, Nikon's gear tends to be bulkier than anything from Pentax. The Pentax SV is still one of the sexiest and best handling film SLRs ever built in my opinion. Both the Nikon F and F2 look as if they were built on the same assembly line as my washing machine. To be fair though, my Nikon F seems to thump right along in the cold weather while the SVs sometimes struggle.
On the lens side, if you like zooms, go with Nikon. If you like primes, go with Pentax. My own opinion of course.