I've been angling to get an X-mount into my kit to play with and ordered a super deal on a basic X-A1 with 16-50mm kit lens on Thursday for a bit under $500. The lens isn't great so could sell it and have a really good, APSC imaging engine with a very short flange distance for under $300.
The exciting part comes when you head over to eBay and find adapters to allow darn near any kind of lens mount to be adapted to the Fuji X to use in manual mode. There's even tilt-and-shift adapters! YAY!! 55mm & 105mm Nikon macro lens now with added T&S capability on a crop sensor.
I think I'll have a lot of fun with this thing and the pile of various (Nikon, Pentax, Olympus, Canon, M42, T-mount, etc) glass I already have.
I don't much care for the ergonomics on this little camera but it won't matter since it'll likely live on a tripod most of the time and the tilt display and WiFi may be useful.
If I enjoy the Fuji way of doing things then an X-E2 or whatever the new X-pro gets updated to might be on the get list next year. Hopefully by then there'll also be better support for the X-trans demosaicing than there is now, which is another reason, other than being really cheap, I went with the Bayer-filtered sensor in the A-1 for now.
I think the APSC X-mount is more of an operational sweet-spot than a MFT body. If only Pentax had made a versatile, short register body instead of the K-01...