Lea Verou just published a blog post about the LCH color space. This is super exciting, see her post for detail. Specifically, the improvement has to do with the perceptual uniformity and lightness being visually consistent no matter the hue.
The best way to get a feel for this is to experiment with her LCH color picker. Drag the hue value back and forth, and you’ll see that the tonality of the background remains consistent. It doesn’t suddenly feel a lot lighter in yellow than it does in blue. Do the same thing in an HSL color picker and you’ll feel the difference.
This would help a lot with the color on my site. I’ve never been 100% happy with how the color is handled because it is too hard to control the lightness and thus the legibility. See the List page for a clear example of this, posts in June and February are particularly hard to read. LCH would solve this!