I own both, have used Nikon's since 1978 and bought the Fuji X-T1 on launch in Canada sight unseen. Overall I was pretty happy and bought the XF14mm F2.8, XF23mm 1.4, XF56mm 1.2 and the XF55-200mm f3.5-4.8 mostly as a travel kit when I wanted to haul less gear.
The relationship with the X-T1 hasn't gone so well and I have since purged the primes, added the XF16-55mm F2.8 and kept the 55-200. Ergonomic niggles confound me with this camera, it eats batteries(I had to buy 6 to keep it running for extended periods), exposure bracketing is pathetic, the buttons on the back are not responsive enough and just too small, the drive and metering dial are way too loose and get moved when the camera strap is wrapped around my wrist. I could go on but why kick a horse when it is down? Anyway, I am keeping it BUT only as a compact lighter alternative, it certainly isn't a replacement for my Nikon's.