I'm not typically a huge fan of fine tipped writing utencils. However, the more time I spend working on my bullet journal, the more I realize that they do have benefits and should not be written off completely.
That being said, I am still extremely picky about the ones I use and these are some of the best ones out there that I have tried. The colors are great, the .4mm size is a really good size and they don't seem to run on any of the paper I have used them on. Unfortunately, if you are using thinner paper, you most likely will experience bleed through to the other size. Other than that, I have no complaints. And actually, since I tend to use thicker, higher quality paper, this is rarely a problem for me at all.