[Semiapies]

I've known people with vision problems who have to skip light-on-dark web pages because it's just not tenable for them to try to read. (This was before Readability, though keep in mind it's nobody's obligation to find a work-around for your eye-straining website.)

I suspect there's an objective benefit, there.

Everything seems to indicate that dark-on-light is better than light-on-dark, and both are better than light-on-light or dark-on-dark. (Or, in other words, contrast is vital, and dark text is preferable.)