Brush pens are just about the best damn thing ever. I've always loved working with black ink, but with brushes there's too much clean-up for me to do it on the fly. Brush pens, on the other hand, give similar results (lineart-wise, anyway) and are totally portable. Ink at work! Ink in bed! Ink while watching Angel DVDs with friends! Yes! Perfect art tool. I've only had mine since last week and I've already used up a whole ink cartridge just playing around with it. A few of the results are now posted in the Inks section of the Art page.