Bottom line for me (my opinion and worth what freely given opinions are always worth) the Fuji X-Pro / X-E1 (I don't have an X-M1 but it's the same sensor) stands up well enough against the Sony full frame RX1 that I don't think up-grading is worth it for most people. Most people wouldn't buy the Sony anyway because it is quite expensive. I know, the Fuji is more expensive, especially with the really nice 35 f1.4 lens, than a sane person would spend on a camera anyway. I bought this one, that's about a year old, for a grand less than the new price but I bought the X-E1 (w/ lens) for about half of what it cost new. I don't have the new 23mm f1.4 XF lens yet (not even sure it's out) and that would be a more appropriate comparison but if it's as good as the 35, it will be a knockout.
The Sony field of view at 35mm suits me well. That's an individual preference. Most days I'd rather have the 35 over the 50mm effective fov of (this) Fuji. The build quality, somewhat smaller size, larger (world class) sensor magic, sharp (world class) Zeiss lens, are all in the Sony's favor. But the Fuji is only a bit larger; it's build quality is still good; it has a built in EVF, which is terrific; it has the extra dial for setting shutter speeds manually; and it allows for a variety of lenses because it isn't a fixed lens camera like the Sony. But like a Leica, if you want world class sensor and lens and can live with the 35mm fov and money's not the only determining factor, I can see buying the Sony. It is cheaper than going the Leica full frame route (a lot cheaper) and the output, apples to apples (35mm Summicron) is quite comparable. But if you don't need or want a Leica, or it's output and just want super photos with great camera control, the Fuji is plenty good enough to stand up to the Sony and look it in the eye and not blink.
[errata: I know Sony's in the process of introducing a full frame system camera which will allow for interchangeable lenses. The limiting factor, here, initially, will be the lenses that will be available when it's produced. They aren't yet up to the speed standard of this RX1 lens. I've also tried adapting Leica glass / including Voigtlander to system cameras with adapters and well, digital cameras work best with lenses designed to work with a specific sensor. I still fit CV lenses to other cameras, including the Fuji, once in a while but ultimately it is a compromise. The new camera [A7] looks great but for quite a while, the RX1 will be a pretty cool choice for folks who want fast glass and full frame in a very small body.]
After posting, I see Steve Huff did something similar a long time ago, if you are interested:
http://www.stevehuffphoto.com/2013/01/18/quick-comparison-sony-rx1-vs-fuji-x-e1-iq-af-speed-and-iso/