That’s how I feel about my Df. I bought my Df back when it came out and when I retired from commercial photography I kept my Df. As you’re doing I only use vintage AIs primes on it.
Good one. If I had a Nikon Df I would surely keep it too.
I feel much the same way about my two D800s. They are about as good as Nikon cameras will ever get, for my needs and wants. Sure, now and then I fantasize about buying one of those new Zf rigs but at AUD $4000 for the camera (no lens) alone, it's unlikely I will ever save up enough from my pension income to pay for such an extravagance. So D800s it will be, for the rest of my time.
Admittedly this is somewhat off-topic, but I will try to redeem myself by saying I greatly admire those who can afford to, and decide to buy one of the new Zfs. It looks to me to be as good as mirrorless cameras will ever get.I mean, until Nikon or Canon or one of the big boys gives us a kit with a built-in barista quality coffee maker, what more can they add to make cameras any better than they are now?
One of my D800s has a damaged slot (the big one) which I unintentionally did when I inserted my new 64 card the wrong way. Bent a pin and her pin Ozzy where everything including toothpicks cost almost as much as you would get on the black economy for one of your kidneys, the cost of repairing this alone means I have to forego a few goodies for a time. So for now I am using the camera with the small slot only. It does the job as well as before, if (and they may be imagining on my part) a tad more slow in loading the image. A fraction of second at most. So I make do, and take consolation in being able to save the AUD $400 repair job for a new slot until I've saved up enough.
We pay much too much for anything to do with camera stuff here in Australia. Partly to do with our miserable South Pacific Peso (worth all of 66 US cents as I type this post) but also due to the high costs of everything in a country with a small population and business intent on making 200% profit on everything they sell. But I am not really complaining. I will get that damn D800 slot fixed when I'm in Singapore or Kuala Lumpur next. Repairs even in expensive Singapore are a fraction of what I will have to pay in Melbourne. Lesson learned.
Back to the Zf. It looks a marvelous machine, and if I get super good lucky and win a lottery (unlikely as I don't buy lotto tickets), it will be the first thing I'lll buy. With a Z lens adaptor to use my collection of good D lenses on it. Manual focusing I can live with.
So yes, I envy you all to be able to afford such a lovely beast. And I hope my time will come. It would be an ideal last camera for me, tho' I will be leery of selling my beloved D800s which have served me so well and continue to do so.
We are indeed lucky to live in a time when so many good Nikons are available to us.