I have been evaluating this camera for more than a week and comparing it against a Nikon 1 J3 plus my other older cameras. I have been a Canon guy over the years, and I currently have a P&S, a G series, and a DSLR from Canon, all of which are getting old so I was looking to get a large-sensor mirrorless camera.
In many ways this camera points towards the future of non-phone cameras: it has a large sensor (bigger than a phone is ever likely to have), wifi connectivity for immediate upload and sharing, and large touch screen with smartphone like gestures (zoom, swipe, etc).
The best thing about this camera is the UI. With a couple of screen touches, you can change just about any setting. There is an awesome touch-focus-snap feature that allows you to focus where your finger is on the live image, and immediately take a shot. After using the touchscreen, any other camera without it looks primitive. The touch screen is great for taking photos as well as reviewing the results later.
Wifi connectivity is also nice. It allows you to upload to Facebook, Picasa, Youtube, and Microsoft SkyDrive. I used the latter since it is like Dropbox - a good place to back up files for post-processing later on my PC. Wifi worked well.
Lastly, because the sensor is APS-C size (like on most DSLRs), you get a nice shallow depth of field (bokeh blurry background) which is hard-to-impossible to obtain with smaller sensors.
Image quality is closer to point-and-shoot than SLR. This shocked to me, given the large sensor. I attribute it to the image processor rather than sensor or lens. The images have a slightly pastel-blur quality to them (when viewed zoomed in) that I have last seen on an old Sony point-and-shoot I had 5 years ago. Looks like an image processing and compression artifact to me. Also, the level of noise at high ISO looks identical to that of the Nikon 1, whose sensor is 3x smaller.
Auto white balance is also a bit off, at least on mine. It tends to produce slighly cooler tones, especially compared to the Nikon 1. Under indoor lights, when manually set to tungsten, the color matches the Nikon's auto white balance, but it is clear which company makes cameras and which one makes cell phones.
Auto focus is slow and sometimes impossible under low light. This is very frustrating when trying to photograph kids - the moment will be gone by the time you are ready. Interestingly, if you use the touch-focus feature on the screen, the camera is much more likely to focus correctly, when the shutter button focus fails to focus. I guess there is difference between the shutter button focus trying to evaluate a larger area, while the touch-focus tries to find contrast in a smaller area and succeeds. Even so, focus is not as fast as I'd like (and slower than an SLR or the Nikon 1). BTW, focus is also likely to be lost during shooting video, especially at low light and longer zoom (50mm on the kit lens) and then there is a second or so of trying to lock on again, which is a bit annoying.
Image stabilization is lacking. Most cameras in this class have it either in the body (sensor) or lens. Not here. The kit 20-50mm lens is not stabilized. This makes a difference in low light situations and when shooting video.
Lastly, the physical buttons and controls on the camera suck. It would have been nice to have a normal PASM selector on top like most DSLRs have. Instead, there is a semi-useless selector on top (I avoid using it since it is hard to guess what it will do in what mode).
Not recommended. Image and video quality are more important than UI and Wifi. The Nikon 1 has shown me that phase detect autofocus and image stabilization are necessary in a camera of this type. Samsung NX300 has phase detection, and if its autofocus is faster and better, I may give it a try. Another option is the Sony NEX series, which also has image stabilization and supposedly better image quality from the same size sensor (I have not yet tried it).