The most unique feature of the NX100 in addition to an APS-C sized image sensor in a small body is its i-Function: Engadget found it quite, well, functional. Darren Murph:
The 20mm pancake lens on the model we tested was well built, and the i-Function capabilities were downright impressive. It took us a tick to grok how it works, but a good 30 seconds of learning presented us with loads of on-the-fly flexibility. You simply tap the i-Function button with your right hand in order to select what type of setting you’d like to change (exposure, ISO, shutter speed, etc.), and then rotate the wheel on the lens in either direction in order to change the value.
I’m not sure how I feel about the i-Function. I prefer the lens to be just a lens and not some bastard combination of complex electronics. I guess it already is since in most lenses electrons power the mechanics. But I’m not sure about adding even more. Second, the left hand gets a lot more work. If you photograph manually Samsung’s i-Function may be requiring a bit too much from your left hand: focus, zoom, exposure, ISO, shutter speed, etc. without the right hand doing much else but holding the body and pressing the shutter button. i-Function is certainly unique but I’d prefer both hands getting equal amount of work.
BTW, the NX100 is priced at US$599 (20-50mm) and $649 (20mm) and will be available in October. For all your NX10 users out there you’ll be getting support for i-Function lenses in the same month.