I know the question is aimed at Rez, but I was a bit in the same situation. I didn't know much about JS (but I knew other languages: VB, notions of C/C++, PHP, Lua/python) and found JS quite straight forward to get into.
Especially in the goal of plugin developpement for C2, Ashley made an awesome SDK with links to JS guides and references and from there it was almost like "follow the guide".
In the end, I found it pretty easy and fun to developp plugin or behavior for C2 even if sometimes you will encounter your fair share of headaches, but that's what dev is about in my experience <img src="smileys/smiley1.gif" border="0" align="middle">