Luminance in “video” mode has every appearance of being a standard Rec. 709 encoding, and fills the waveform monitor correctly with a probably-acceptable overshoot of super-whites. In “film” mode, the live output appears to be considerably reduced in dynamic range as one would expect; however, with very extreme overexposure, it is still possible to clip the graph and drive the image sensor into the same solarised peak whites as the 2.5K camera under similar circumstances (though this is an edge case and easy to fix in post). Experiments with closing the iris one stop at a time confirm that the encoding is approximately logarithmic. Presumably, LUTs for monitors could be designed in Resolve and output to something like the company's HDlink, which is certainly accurate enough for casual, on-set viewing.
No raw option yet
It's impossible to be certain about the quality of the internal dåebayer until the raw option appears, at which point we'll hopefully have the option to compare it with alternatives. Recovering RGB images from a quad-HD Bayer sensor is not trivial in terms of computational horsepower, and one of the advantages of raw shooting – apart from the lack of compression and the usually-improved dynamic range – is the option to throw the comparatively huge power of a desktop workstation at the problem.
So, with a caveat about the missing audio metering and disk space monitoring, I'd call this a very reasonable way of getting into 4K for a rock-bottom price. The real usefulness of it depends on your reason for getting into 4K in the first place. If you have clients who demand it but aren't willing to fund the high-end options, this is clearly interesting. If your interest is more in increasing the quality of your HD productions by mastering at 4K, then you may need to evaluate whether the noise and dynamic range tradeoff works for you, because the original cinema camera was very solid in this regard if you can stand the rolling shutter. I think that almost any use will require some bolt-on extras, right up to a full shoulder rig for extended handheld work.
The killer feature is the global shutter, especially in comparison to DSLRs, which tend to have rather slow rolling shutters, and even the predecessor 2.5K Cinema Camera, which wasn't great in that regard. Global shutter is becoming increasingly rare at any level (Alexa lacks it, for instance) and as I wrote recently, I would hope that improved sensor tech will mean that in a few years we'll be looking back on the days of rolling shutter with a grimace and see this as the beginning of a new breed.