In my experience moving from a 6D to a XE-2 there were more than a few jarring adjustments that initially made me think about going back to a DSLR. The three with Fuji for me were:
- Battery life is HORRENDOUS. Instead of carrying 1-2 spares, I'm carrying 3-4. Granted the batteries are smaller, but there's no denying the lack of battery life for mirrorless.
- The AF is nowhere near as good as even an entry-level DSLR. I'm not talking acquisition speed because phase detect is more than good enough. I'm talking low-light lock ability and tracking ability. I could make do with my 6D's center point when shooting the odd sport. With my Fuji, I get maybe 50-60% as many keepers. And in low-light, my 6D was almost always accurate using the center point. I can't say the same with my Fuji.
- The high-iso noise reduction for Fuji is very aggressive. VERY aggressive.
And that's on top of the stress of moving to a completely different system.
If you can Euro, try and find a place that'll rent whatever you think you might want to try out to you (or borrow a friend's). I've learned to live with the shortcomings that bug me because not only was I actually taking photos for once and not leaving my camera at home because it was too big, but also because I was getting 90% of what I was used to getting with my 6D in a way smaller package. I've even found that I'm post-processing less because the Fuji jpegs are beautiful most of the time.
You undoubtedly find your own issues with mirrorless because they aren't direct replacements to a DSLR. But if you get past them, I have no doubt you'll enjoy using it more than any DSLR.
(this is assuming you're not a professional shooting paid gigs, and the camera is strictly for pleasure)