When comparing Parenscript vs Earl Grey, the Slant community recommends Earl Grey for most people. In the question“What are the best languages that compile to JavaScript? ” Earl Grey is ranked 29th while Parenscript is ranked 35th. The most important reason people chose Earl Grey is:
Earl Grey's macro system allows for creating powerful control structures that look just like builtin ones. EG also supports macro libraries which allows developers to provide their macros/DSLs for others to use.
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Pros

Pro It is Common Lisp
Lisps are easy languages to learn (once you get past the parens) and Common Lisp is a very practical dialect.
Pro Run almost identically on both the browser and server
Parenscript code can run almost identically on both the browser (as JavaScript) and server (as Common Lisp).
Pro Powerful hygienic macros
Earl Grey's macro system allows for creating powerful control structures that look just like builtin ones. EG also supports macro libraries which allows developers to provide their macros/DSLs for others to use.
Pro Pattern matching
Pattern matching is an incredibly powerful tool that, once you've tried, you cannot live without. This is not your average hacked-together pattern matching but a complete and integral feature to the language.
Pro ECMAScript 6 Asynchrony
Earl Grey provides Promises based on ECMAScript version 6 and as many NPM libraries already implement. Earl Grey also provides a promisify
function that converts old-fashioned callback-style asynchrony to promises.
Pro Fully compatible with Node.js ecosystem
Anything available on NPM can be used just as easily with Earl Grey. In fact, everything else can be used too! Earl Grey has interfaces to Browserify, Webpack, and even experimental support for SystemJS. Earl Grey can even be used to generate npm packages that any node-compatible language can use!
Cons
Con The syntax may be hard to learn
Being an implementation of Lisp, Parenscript's syntax may seem cryptic and hard to understand for people not used to it. While Lisp has very little syntax compared to other languages and it's generally considered pretty terse, there's still an initial overhead in learning the language.
Con Not true static typing
EG gives you the tools to implement your own type-checking inside of argument lists and elsewhere but there's no analysis done at compile-time like other compile-to-js languages.
Con Unfamiliar syntax
While the language shares a lot of DNA with Python, there are still many new (and interesting) features/sugar that may take some time to get used to.
