There's a question I've been getting in my inbox every couple of days since the release of the Fujifilm X-T2: Is it ready for professional use? There have been several articles floating about and a lot of opinions in forums, but the honest answer to this is the same as it is for absolutely every camera body and system on the market. It really depends on the type of work you do.
There is no debating that Fujifilm has some of the best image quality in the small sensor market. Not only is their color rendition wonderfully natural, but the dynamic range and ISO performance is among the best. Sharpness is excellent, especially when paired with the gorgeous collection of prime lenses Fujifilm offers.
Personally, I have no troubles substituting my Nikon D750 with the X-T2 when it comes to image quality. In fact, for many applications, especially portraits and food, I actually prefer the more natural rendering that I get from the Fujifilm X-T2. The gradation of color and transitions from shadow to highlight are more pleasing to my eye.
Pushing the files to their limits shows where perhaps a full-frame sensor may still have a slight edge. At high ISOs, the Fujifilm X-T2 tends to lose highlight details and produce purple shadows at about 1/2 stop before the Nikon D750 in my testing. Not a huge difference. But, if you're really looking to push the files, perhaps the X-T2 isn't the right choice.