Which Ink Should I Choose?

Making a video about my journals was so much fun, I thought I would do it again with some inks. Since I have a gazillion inks (the actual number), I thought I would narrow it down to one color and one brand. The color had to be blue, of course, cuz we're talking about me. And the brand is Pilot Iroshizuku, as suggested to me by Overall Adventures. (I promise I'm not stalking her.) What will I choose? What SHOULD I choose? And which one would you choose? Could you write with only one ink in your journal for a month or more?