From the (incomplete) overview here (and ignoring the type system for the moment), Dart appears to be reasonably competent and technically sound, given that this is a language intended to compile to Javascript. That said, it doesn't terribly excite me.<p>It should be interesting to see whether the safety guarantees of optional typing and the few other restrictions it provides (such as more rigid function signatures) will really entice developers who are planning large web applications. I'm working on a modest-sized (~3kloc) Javascript codebase at the moment and it's somewhat of a mess, but that's really more due to the combined influence of legacy code, time constraints, technical debt, rapidly shifting requirements, and a lack of testing. Other than that last point, it's not immediately obvious how using Dart rather than Javascript would have benefited me. Perhaps someone who's worked with a more substantial Javascript application could provide a better answer.