@Luke will shake his head (or laugh his head off) at this. But I simply had to try one before writing off the system.
So far, I like the camera in the hand, and I like the results (a lot, in fact - specifically, I get the thing about Fuji JPEGs now; I have no serious reservations of using the images SOOC). But it certainly doesn't supplant the technologically superior cameras, specifically the GX9 with its faster operation, I.B.I.S. and smaller lenses.
However, I'll probably keep it (it's near mint, and I got it at the price of the lens alone) because it has effectively silenced my desire to get a Leica CL with the 18-56mm in order to have a Leica-like zoom camera, something the GX9 is just doesn't represent for me, in spite of the form factor (and I've tried hard to see and use it that way, believe me). In short, the Fuji makes a congenial partner for the M cameras because it can do duty as a second, versatile (i.e. zoom) body alongside them without breaking the flow (too much).
I've so far used the G1X III for that task most of the time. It's a bit like comparing apples and oranges, but since the X-E3 does fit into my ONA Bowery together with an M, it's a viable comparison nonetheless. The Fuji delivers better images than the Canon (though the difference isn't as big as some may think) which in turn is obviously the better pocket camera (heck, so's the M8 with the Voigtländer Nokton Classic!). But the 18-55mm is also a very compelling lens in use - way nicer than the Canon's power zoom. So, for more dedicated photography, I do prefer the larger setup already. The G1X III is unbeatable for its size and sturdiness (weather protection!) - it's the camera I take if I'm hesitant about taking a camera at all ... but it'll see less use as a sidekick.
Just one thing: If someone knows a way to inverse the direction of the aperture ring, I'd be grateful.