The colour is a striking version of blue that reminds me of blue marker ink actually. If you're a watercolour user, you can think of this ink as the darker version of Phthalo Blue.
This ink has a good contrast against paper.
For writing and drawing purposes, this ink performs well. There's an attractive sheen, a gradation of colour, to the strokes.
As a main ink for writing, I think it's a bit too glaring. My preference would be for a darker and duller ink such as Shin Kai.
Below are direct links to the ink on Amazon.