The PITTs are about as good as it gets in a disposable pen. Although the Copic multiliners are good too. The Copic ink isn't water-based though, I think it's some kind of ammonia based solvent, judging from the smell, and if you've done much erasure prior to inking (something I am very wont to do) it seems to bleed more than the PITT ink. So I would say that PITTs are the best disposables out there.