If anything, I'd say Fuji's colors are better than everyone else's,
Of course you would say that. You bought a Fuji and you bought it because of what you read/heard/thought about its colour performance.
In fact, most Fuji owners probably think Fuji produces the best colours. If they didn't why did they buy Fuji? If they bought it and found they didn't like the colours why would they keep it?
For a more objective evaluation, you need to do tests where the same subject is photographed under the same light on many brands of camera, and then have the output evaluated by people with a background evaluating images, without them knowing which brand took which image. I only know of one such test. It was conducted about a year ago by The Camera Store. Default JPEG colours were evaluated using a portrait, a landscape and a studio shot that included a colour checker. Fuji finished fourth of eight. The Fuji body used in the test was the X-T2.
though my experience is primarily related to JPEG. I bought the X-T2 because of the Fuji colors and the film simulations. With all other cameras I've owned, RAW processing was necessary with every single image in order to achieve satisfactory results. With Fuji, I usually use the JPEG (as long as I got it with the right film simulation).
The idea of color differences in RAW between brands I'd say is pretty far fetched. With RAW you can use film simulation software like RNI and pretty much achieve whatever color you want.
I agree that colour output evaluation is pretty much limited to default JPEG output. Most cameras let you adjust JPEG output from the deftult settings, an dRAW offers even more flexibility.