In short, the main difference lies in the ink, and the way that impacts the writing experience. Liquid ink and the tiny rollerball in the tip helps rollerball pens glide effortlessly over paper for free-flowing, fluid writing. Gel pens use a thicker, liquid gel ink to deliver vibrant colors and bold lines. Ballpoint pens are known for their durability and longevity, and their ink tends to be quick-drying and more naturally smudge-resistent. While many ballpoint pens traditionally use oil-based inks, uniball ballpoint pens use a unique hybrid formulation—part of the reason our top-rated JETSTREAM ballpoint pens are known for their incredibly fast and effortless writing.