I *love* these pens. They are the same to write with if you are familiar with the Marvy LePen - but they are better colors. I've also occasionally had the LePen let out too much ink, and these don't do that.
I love the colors of the Bright set. They are somewhat muted, and more classic, which is what I was looking for. They would probably bleed or ghost through on thinner paper, but if you're using a higher quality BuJo/ journal, you should be fine.