Mypaint's delayed brushes are cool for line quality, but I think the speed may be too slow for some. Otherwise, Mypaint, Gimp and Krita are all fast enough for my purposes. Maybe the speed has something to do with the human perception of time -- I'm very slow, my reflexes etc. are slow.

@Griatch: the comic is a elaborate two page joke, theme is magic. Nothing special. I'll tell when I publish something longer... XD