The American Falls - Pentax Q with 8.5mm f1.9 lens. Click for larger.
The Nikon J1 and Pentax Q cost about the same when introduced, and at the end of product life cycle, less than a year later, both are selling at less than half of the new price. If both of these products were something like $400 to start with, I think the situation would be very different. Enough rant, on to the Pentax Q.
The Pentax Q is a neat little camera. Cute as a button, and almost toy like in appearance, but it's a very well built camera, similar to the Panasonic LX series. In fact, holding both the LX2 and Pentax Q with the 01 standard lens at the same time, both weigh about the same and have similar heft, though the LX-2 is actually slightly larger. The selling point of the Q is of course its lens interchangeable feature. Mine comes with the 8.5mm (about 50mm) f1.9 standard lens.
Salt Truck - Pentax Q & 8.5mm f1.9 lens. Click for larger.
Despite its small size, handling is surprisingly good. Better than a lot of point & shoots with similar size.
Image quality is nowhere near the NEX-6. If image quality is your primary concern, this is not the camera for you. But, I find it very good for the small sensor, especially when shooting RAW, up to ISO 400 is very usable. The 01 standard lens that came with my Q is not particularly good, not sure if it's the sensor or the lens, but pictures taken with the combination is not very sharp. Since I don't have other lenses, I can't say if it's the lens. I have ordered a C-mount and D-mount adapters for it, but it will take a few weeks to arrive from China.
Is it worth the money? It depends on how much you pay for it. This camera does allow you to use some very wide angle c-mount lenses which are not usable on M4/3 or NEX. Even the smaller D-mount lenses can be used. So, it's a fun camera. Buy it for its fun factor, but not for its image quality, which is not bad but not on-par with M4/3 or APS-C sensors.
Mellow Yellow - Pentax Q & 8.5mm f1.9 Lens. Click for larger.