Agreed, Observable fixes a lot of the problems I've had with other notebooks. It can still be fiddly for code over a certain size/ complexity but the ability to import from npm modules goes a long way to fixing the problem. The user base seems to be predominantly drawn from the visualisation side of things + the fact that it's javascript may limit its uptake in science/maths areas. Aside: I've felt for a while that JS is really missing decent maths/stats libraries, any suggestions?