You value image rendering, got lots of old Nikkors and new Zeiss, you walk and hike, and already have a 36 Mpix camera : you tick all the boxes... get it.
I bought a Df in May 2014 and since then, I've been using it nearly every day (!) and on every trip, and with all sorts of lenses, mosty manual focus.
For full happiness, consider buying a magnifying eyepiece (DK-17M).
I've used other digital cameras, including D700, D800, OM-D E-M1. The Df pics look most natural to me and seldom require significant correction in post processing. Compared with the OM-D which I used in parallel for a long time, the latter often produces briliant images, but they have a "chemical" or "processed" character that is absent from Df pics.