I've got the Blue-Black in a couple of pens and like the way it looks. I guess I've used the black, too, since my first fountain pen ink was the cartridge that came with my Parker IM.
The only thing I don't care for is that it's not all that water resistant. This was something I didn't pick up on right away with fountain pen inks, how some of them will wash right off a page. My ideal is an ink that will barely run if I hold a test page under a faucet. By that standard, the Quink doesn't do all that well. Still, most of my writing isn't likely to get soaked.
I'm a fan of Williams, both ancient and modern, by the way.
"...when I attempt a discourse the words come out as they will, and they may make sense when they strike the atmosphere, or they may not." O.Henry - - "Cabbages and Kings"