The 645Z is not an option to most though. Plenty of us have glass that works with a full frame Pentax, and can afford the 2k USD or so a FF Pentax might cost. But 8k or so, plus having to buy new lenses? Which are a few k each? And everything being extremely heavy? Plus a camera that does something like 2 fps or so? That's not an alternative.

The 645Z is a specialist camera for a couple of special purposes, much like an Arri Alexa is too. But it is out of range for most, and probably too much too.

Apparently Samsung has really good lenses, though not many admittedly. Reasonably priced I read somewhere... and lets not forget, it's a mirrorless. It does have a rather long flange distance for a mirrorless (no Leica M lenses then...), but will still take for example Pentax lenses.

Professional support... it's not like Pentax has it either. And only few photographers have access to it anyway, the rest just has 2 bodies if they need to.

Seem like the NX-1 is going to beat the D7100 and K-3 to the next Photokina or CP+ in terms or functions and specs. Image quality wise  , lets wait and see.