Right - I include that under the learning curve question. But, that said, there are plenty examples of editors that are obviously not easy to use(cough Emacs?) and yet tons of people still use them because (apparently) they are more productive in Emacs. I'm not one of those people - I tend to prefer TextMate or TextMate-like GUI editors. But I can see how people are willing to suffer through a steep learning curve in order to ultimately become more productive. LightTable might end up being the same way.