When I first got my planner, I wasn't sure which pens I wanted. I ended up with the PaperMate Profile 1.4.
Available in a ton of colors (I forget exactly how many were in the pack I purchased), the pens write fairly well however sometimes have a bit of a hiccup where they don't want to write. They don't bleed through the EC Life Planner pages, but they're not always the smoothest things to write with. I haven't yet experienced the favorite Flixion erasable pens that every planner addict seems to love, but they may be next on my list to try. I definitely don't hate the Profiles and will keep them, but I would probably rate them a 7 out of 10.