Impressions of the Fuji X-T2 vs 6D to this point:
+ Fuji lenses are SHARP. The 50-140 2.8 is freakishly sharp, even wide open
+ Much more portable
+ EVF vs DSLR viewfinder
+ Joystick for AF selection is great
+ 4K video is really, really nice. Glad to have 24p native as an option
+ Increased frame rate for still captures is nice to have
+ Dual SD is very nice for piece of mind (mirroring each other)
+ Physical dials for ISO, shutter speed, aperture (on supported lenses), autofocus modes, and exposure modes are incredible and I don't really ever want to use a camera that relies on scroll wheels again
+ JPEGs SooC are leagues better than Canon JPEGs
- Atrocious battery life, around 200-300 shots per battery. This is about 1/3rd the 6D
- Awkward ergonomics with larger lenses like the 50-140 if you don't buy the $350 battery grip
- Audio in video captures is far worse than the stock 6D with no external mic
- Usable ISO range is obviously considerably lower than the full frame 6D, but finding I really don't like pushing past 1600 on the Fuji. I was comfortable on the Canon up to 6400.
- Camera strap eyelet is really poorly placed on the right side (while holding), nearly always interferes with my grip
- Flip out screen doesn't rotate for "selfie mode" (more a comparison against the 6D MkII though)
The one major issue I have at this point is how Lightroom handles Fuji's RAF files. It's just about impossible to sharpen a RAF in Lightroom without introducing "worms". I am very possibly going to have to change my entire RAW workflow because of this. I'm playing with Capture One, but am not sold on it yet, as it seems to apply a fair amount of processing to RAF files by default (warmer and more noise than LR). However, Capture One can really crank up the sharpening with almost no ill effects on the file.
Time will tell on this swap, I'm having to relearn in almost every area of the camera, but so far have gotten pretty good results all told.