The good news is that this is a pleasant shade of blue, and it really is very permanent. It is nicely resistant to bleeding and feathering, and it dries to an attractive matte texture on the paper.
The color is rather weak, which is to say that it appears to be relatively light and unsaturated compared with many inks these days. It's sort of an aqua blue. If you demand dark color and saturation, you might steer away.
As a pigmented ink, one expects this to be a bit finicky and require more regular and perhaps more thorough cleaning than typical inks, and I found that to be true. This is not for pens that will be left neglected, and you probably should flush between fills rather than merely fill-and-write, fill-and-write, etc. I would not use it in pens that are difficult to clean. I also had one pen that this ink would not work in, as it simply dripped out of the nib!