Coming from DLSR Systems from Nikon (d7000), Canon (two 40d's and a 7d) and Pentax (K20D, K-x), I have to say I'm pretty much satisfied with this small camera.
I was looking for something to carry around everytime, and nx3000 is a great camera to go out, very small with the powerzoom, or with a Samsung pancake. I paid 265€ for a open box, wich is nothing short of a bargain, specially considering it comes with a copy of Lightroom 5.
Build quality is great(for the price), and I found design very attractive. The lens build quality is good also, without wobbling on extension. Also Ifunc button it's very clever and give you another control ring, making twin control dials in a sub 300€ camera, with is great. Camera battery is good for a day out and usb charging is convenient.
In the other hand, micro SD cards and camera strap are simply a CRAP.
Camera offers great quality in good light, but fails to impress in low light, specially in JPG. In Raw results are a lot more cleaner with a little pp work in Lightroom, but it isn't on par with 4/3 cameras or Sony Nex line. Otherwise, results are good up to higher sensitivities for web use or good sized prints, if you work a little. It also applies to DR, which I found a little restricted compared to it's m 4/3 or Sony peers, but easily worked around thanks to pretty accurate metering.
Working on RAW+jpg slow down the camera too much for my taste.
AF is another weak point of the camera, working great in good light (in photo) but becoming very unreliable and missing a lot in low light. This makes me want to try nx300, which phase detection af would make more usable in low light scenarios.
Also manual focus assist is poorly developed and hard to use because of the magnification which does not allow the user to go back to the full view of the shot when used.
Wifi is great and easy to use when you get used, and also let's you downscale quality to 2mp, which I found convenient. Note that RAW files can not be sent to a smartphone, only jpg files.
Lens is also pretty decent, with a correct stabilizer, and very useful powerzoom for video. Distortion and corner shading is auto corrected at some sharpness wise loose but it's not that bad and I find the compromise in between lens range, quality and small size a pretty handy package. Also AF is good, should be better on nx300.
Overall, I find the camera to be pretty good for a everyday carry out camera, and Samsung lens range is one of the most cheap and good in terms of optical quality, specially if you look at pancakes like the 30mm or fixed focal lenghts.