Sinebow is really nice and smooth, but I'd say there is a bit too much green, and the green that's there is way more saturated than the rest of the colors (perhaps save magenta). The yellow is very sad and desaturated looking. The 0.5 value is also a drab cyan, making it hard to identify. I purposefully didn't include magenta into Turbo, so it could be used as a 'marking' color. Sinebow is also cyclic, which we purposefully didn't want (so that you could tell max from min), but for a color wheel style application this is a plus.

Even closer if you crop it to the part from 0 degrees to 240 degrees.

Sinebow is also much simpler to compute.