Parenscript is nice because you don’t need complicated externs: it has a pretty straightforward mapping to JS symbols and no runtime. However, the downside is that it feels more like “JavaScript with a new syntax” than like Common Lisp or another lisp. I personally find the trade-offs acceptable because it’s fees fairly natural to right JS in a lispy style, but it’s not the “pure” experience of something like Clojurescript.