I'm excited about it precisely because it is a potentially perfect landscape backpacking setup. I've been using Fuji for years, happily, but nearly double the pixel count plus ISO 64 plus an extra stop or more of DR is tempting... The Nikon will probably achieve its peak DR at a lower ISO - the newest XTrans stay right with the D850 at ISO 200 (base on the Fuji), but you get a full extra stop by taking the D850 to ISO 100, and even more by going to ISO 64.
It also has a bigger battery, which is nice for two reasons. Charging individual batteries in the field is a pain - you not only need enough energy (from a battery pack,a solar panel or a wall outlet on a trip to town) to charge the battery, you need to hook up each battery, and that is a pain when you might have seven of them for a weeklong section. The only Fuji USB chargers I've ever found are one battery at a time or too big to backpack with (Nitecore has just released a small, lightweight dual charger for the Fuji batteries, but I haven't seen it for sale). There IS a dual-slot Nikon EN-EL15 charger (weighs 2.5 ozs) available from Nitecore, which is the equivalent of a 4-slot Fuji charger. Easy enough to charge a week's worth in a night in town... Come into town, get two charging, get dinner, change the batteries and go to bed - four charged by morning! The second advantage of the bigger battery is that the power to weight ratio is better - you get more battery per gram of case, circuit board and other things that don't power the camera.