I started using it for a small side-project but had to put it on hold because of issues elsewhere in the stack.
From a cursory glance at things, Duktape looks way more advanced, and being written in pure C should make it much easier to embed. I'll definitely give it a try when I have time to look at that project again.
That said, the TinyJS code is extremely simple, so it makes a potentially good starting point for extending, if you want something JS-like rather than a pure JavaScript engine.
I'm not a huge fan of C++. And that's primarily out of ignorance, I stick with C and leave all the strange syntax wizardy, templates, metatypes to other people.
Also the portability of Duktape impressed me. I was able to get a test up and compiled in cygwin within a few minutes.
