I was debating between 0.7 mm and 0.5 mm and after trying a sample in store I decided on the0.5 mm. Most pens write smoothly although a couple of them don't write very smoothly. Maybe they will improve after more use. Overall I'm satisfied. Next time I will try the 0.7 mm.
I got these for my kids to do their homework because they can never get their pencil point sharp enough. The kids like it. It does write a little lighter than your regular number 2 pencil but still dark enough to read and it gets the job done.