A quick review after using it for a week:
PROS
1) Love the colours + bokeh for a camera this (physical) size!
2) Good low-light performance. Though NR is aggressive; soft looking images. However, cannot complain for compact size cam.
3) Viewfinder! More comfy + stable position to shoot in; akin to DSLR.
CONS
1) Very clunky / non-intuitive interface. Can't beat Nikon Canon interfaces. Throw it to a random friend and they'll pass the cam back to you in 1 min... too difficult to navigate...
2) Weird controls... IMO at least. Don't like the shutter speed knob, EV knob and how the Left-right toggle functions. Would prefer controls of a typical DSLR. Especially missing the rolling-ratchet thumbwheels on your DSLRs. Hope there's a way to re-map the controls to our own functions?
3) Even in decent lighting, AF is a little slow, when compared to my oldish D40
4) Shot-to-shot delay is irritating. 0.5 secs at least. My D40 allows me to snap and take the 2nd shot very quickly. The X100s? "...saving file" zzz... Used .jpeg Large. Other settings seem slower! i.e. RAW / smaller file size jpegs.
5) Full auto settings are wonky. Sometimes good, sometimes overexposed. D40 seemed to nail it 90% of the time.
6) Battery indicator not accurate? It was 3 bars (full) then dropped to 2, 1 and flat in less than 50 shots... Any way to calibrate the battery level indicator?
7) Fixed lens. Indoor room shots are tricky, outdoor landscape shots too. I miss my 18-55 lens... Ok, I'm lazy to leg-zoom
Still learning how to maximize this cam. Fellow users, pls share your tips

Thanks in advance!