Regardng other Pilot Iroshizuku colors, I just tried a sample of mirasaki-shikubu. Based on the swatches, I was really worried that the color would be washed out or faded. I was wrong. I typically like to test my inks with my Noodler's Neponset because it lays down a cubic buttload of ink, I can get decent flexing with little effort on my part, it's easy to test line variation, and the make a swab with the pen instead of using a q-tip. I'm on a work deadline though and was interrupted by the arrival of my first TWSBI. What do I do? Ink it up immediately with the mirasaki-shikubu.
It's a lovely purple that is on the blue side of the spectrum. People's preferences for purple always tend to be towards the red end of the spectrum whereas I love it shifted to the blue spectrum, but not so much that it's mistaken for indigo or dark black. I'm on the hunt for the perfect purple ink ever since Noodler's Violet Vote was discontinued. I'm debating between this ink and Montegrappa Violet. As a reference point, Noodler's Concord Grape is probably my favorite ink, but I know that I have to be really careful with it.
I'm still searching for a good deep red as well. If you find one, let me know!
Hope that was helpful