He's not working with the most recent model and, for that reason, I think his thoughts may be a bit out of date.
I've had the X100s for a little over a year and quite like it. I recently bought an X-T1 and have spend a pretty intensive couple weeks with it. My thought, when I was considering it, was that I might be able to use it as a backup to my D800 and sell my D700. I'd get an adapter to use my Nikon lenses on it. It would lighten my kit bag a bit and provide me with a good, small body to use for street/travel.
I'm not ready to let go of my D700 yet. The X-T1 is a very good camera and, like all the X-Trans cameras, produces excellent pictures. In terms of the quality of the photos, I have no qualms. But there are some aspects of it that are giving me pause and making think really hard before deciding to sell the D700.