[jrumbut]

I think in some ways the problems people have experienced come back to a language design that is fairly ambitious.

Specifically the inclusion of a prototype OO system is confusing if you aren't aware what that is and have only been exposed to Java-like OO programming. But in fact it's very powerful and not so hard to learn once you realize you have to.

As with other web technologies, it's simple at first glance but the learning curve gets steeper at some point.