I have only used the camera in 4:4:4 mode. In 4:4:4 mode you have no color controls. I would much rather do the color correction later. There is ways to view a look on your monitor, while preserving the raw data. You can set look up tables on the S2 for rough looks, but I hardly played around with that to much. For the look of the upcoming Heineken spot I shot for Fincher, I was able to pull off stills from the S2 hard drives and color correct them later to be used as references. Once the spot releases, I will show the reference on my site. You will be able to see the RAW file and the final side by side www.claudiomiranda.com.
The Viper deals well with highlights and low lights. For Xelibri, some of the practicals in shot light the people without blowing out or any other video artifact. On Heineken, we lit the street scence to very low levels. Letting the street lights blow. Shooting wide open for the most part. If you go too far in the toe end of the range, it does get a little noisy. You can get a better darker image if it is initially up, then crush it later. This helps eliminate the noise in the blacks.