Good to know, thanks Nick.
Now, are accurate colors a garantee of pleasant skin tones?
Delta E measurements on color accuracy are mostly meaningless for general-purpose photography. Delta E only makes sense for a colorimetric ("scene-referred") profile, which requires that there is no contrast curve applied, and you use this only for reproduction work. For any general-purpose photography you apply a "film curve" and then you throw out any Delta E numbers through the window. Still anyone knows that a film curve is required to make a normal scene to look realistic, linear curve looks flat and dull. There is however no standard to measure "perceptual accuracy", that is how realistic colors look after the film curve is applied.
In our color perception contrast and saturation is connected. If you increase contrast you must also increase saturation, otherwise colors will appear desaturated. But there are also other more subtle effects.
When it comes to "pleasing skin tones", my experience from color profile design is that the hue/saturation is only a one part of the problem, how the colors rolls off into the white point is very important for the look, especially for high key portraits. The shadow range of the curve also needs a small saturation push to not look desaturated, and then on top you can add "beutifying" modifications like compressing the skintone hue range to even out skin.
Profile designers available to photographers are generally good at making reproduction profiles, but has generally no strategy at all to convert that reproduction profile to a general purpose profile when a curve is applied, but instead just put a RGB or a RGB-HSV (DNG-style) curve on top which does increase saturation, but not in a perceptually accurate way, or even a pleasing way.
Commercial profiles are designed with inhouse tools, unavailable to users. It's very difficult to replicate and is an important part of the "trade secret" that sells cameras.
Personally I think Hasselblad is the best of medium format brands when it comes to profile design, but it's a matter of taste of course. Hasselblad's approach is to make a profile that focuses to a large extent on perceptual accuracy, and then add only very subtle subjective adjustments on top (plus a pretty strong gamut compression). If you look at say Phase One and Leaf they're much more about creating a "brand look", Phase One has their famous yellow cast for example. Their profiles are still very well-designed though, but with a distinct look which you may like or not. Worst are those that in practice are used together with third-party raw converters like Lightroom. Pentax, Leica(?) whose Lightroom profiles are pretty dreadful.
Hasselblad's colors are good also with the older CCDs which actually are quite difficult to work with due to Kodak-style subjective elements in the CFA. With the newer more neutral and extremely low noise CMOS sensors there's a better base to build color on, I haven't personally had a deep look on any of the newer Hassy backs but I have no reason to doubt that their color is still excellent.
