In the past few years Diamine has released several series of shimmering inks. Night sky is one of those ink, a black color with silver shimmer in it. The shimmer makes it a bit of a gimmick of course. You will get away with it in the office (for note taking), but the amount of shimmer is definitely noticeable. It looks a it as if someone wrote with a pencil over your black ink. The color is pleasant to read, which makes it suitable for personal notes. For me, I think inks with this high level of shimmer are best used for invitation cards, short notes, or maybe greeting cards.
The ink is good, but not excellent. No feathering, minimal show-through, some shading, well lubricated and wet but not too wet. Drying time is long, 50 seconds, but it's not unheard of for a dark, black ink. Be careful with fluids. You will still see what you wrote, but you will have to rewrite the page. The amount of shimmer in this ink is quite high, much higher than in Herbin inks.Not so easy to catch it on the scanner, but it's clearly visible on paper. I have noticed some 'hard starts' with this ink, something I have never observed in Diamine inks before.
The broad oblique nib brought out some silver sheen you can't see with either the glass dip pen or the TWSBI with broad nib.
Comparing the inks to others seemed a bit pointless. I don't have any comparable black inks, just black inks. So instead the paper shows the different between one, two and three brushes with a q-tip swap.