The thing I really noticed is that I could write for much longer with far less wrist fatigue. They are just incredible and underappreciated pens. If you write a lot, then they are really worth it. I also suggest not buying cartridges but refillers. Bulletproof inks are just superior to anything else I've used in even fancy pens, where the ink won't bleed or go away until basically the paper does too. It's also nice to have some unique colors, not to mention saves on a lot of plastic (and ink can be useful for other things).