Hi Captain, I have been shooting with the XPro1 and Leica M lenses since August and I have to say I really enjoy the experience. My lenses are v1 and v4 35/2, v3 28/2.8, v5 50/2, 90 tele-elmarit and a 135 elmar. I use the Fuji M adapter. I also have the Fuji 35/1.4 which I use very rarely. It's a great lens but its A very different kind of camera with it on.
I can't compare with the Ricoh or Sony NEX since I haven't used them. Focusing is veery easy with the evf. The OVF is neat but very hard to see in daylight. Also the OVF frame lines stop at 60mm so the tele lenses have to use the evf for accurate framing.
I find it best to use aperture priority and manual iso. In auto iso the shutter speed defaults to 1/30th even though the camera knows what lens you are using through the adapter.
The image quality is really very good. I hope this helps. Please feel free to ask anything more pointed.
Kwesi