Cameras in this price range usually cause concern with their build and feel, but ePHOTOzine calls the NX3000 "well built" and says even the lens doesn't come off like a "budget" item. And thanks to its diminutive size, What Digital Camera states that even with the lens, the NX3000 can "comfortably" fit in your bag.
In use things are fairly good for the NX3000, with ePHOTOzine experiencing "reasonable" focus speeds, though PC Mag feels the "2.2 second" startup time "is on the slow side." Once you've got the camera ready to shoot you'll at least be treated to what Photography Blog says is "excellent" photo quality, with Trusted Reviews noting that while shots in "good conditions" are "excellent," things start to "falter" in more challenging situations. However, the NX3000 is considered an entry-level camera and it costs less than $500, so some issues are to be expected.
At the end of the day the NX3000 is simply an affordable, lens-flexible camera that fits the needs of low-budget shoppers. It shouldn't be your first choice if you're really serious about photography, but if you just want to shoot some vacation photos or a school play it will serve you well. And, with a price point under $500, you'll still have some cash left over for an extra lens.