The main difference is the ink. In ballpoint pens, the ink is an oil-based paste ink that dries immediately. It is suited to all types of writing styles. The frustration some people feel with ballpoint pens usually involves an inferior brand of pen that makes blobs or skips. High quality ballpoint pens do not do this.

On the other hand, the ink of a rollerball pen is more fluid than ballpoint ink, so it seldom skips, but the ink does take a few seconds to dry. The ink in a rollerball also runs out sooner than in a ballpoint, requiring more frequent refills.