Apparently I'm not a dark brown fan, because I've had a pen inked with this for a week, and I just don't find myself reaching for it often at all. Which is a pity, because there is nothing wrong with the color -- it is a deep, walnutty brown, and it looks fantastic on off-white paper. It's also one of the best behaved of all the sample inks that I bought: zero feathering, quick dry time, no clogging.
Maybe it's the lack of shading potential that gets me? Whatever the case, if someone is looking for a dark, extremely obedient brown with very little variation in color, this is probably it.