gistfile1.txt

RingoJs

Ease of use
 + Easy deployment (as deb or to appengine)
 + REPL with auto-completion & history
 + Mostly implemented in JS (ongoing effort)
 + Jetty webserver (out-of-box serving)
 + Graphical debugger
 o API docs, open Wiki (still a lot missing)
 - ...

Features / Design
 + Amongst best CommonJs compliance
 + rock solid runtime (10 years experience running SSJS on JVM)
 + Full featured Web Framework (templates, request dispatch, sessions,..)
 + Easy access to Java libraries
 + Implemented mostly in JS
 o Speed (it's not V8 but Rhino shines in RingoJs)
 - ...
 
Maturity
 o Powers small scale sites. Nearing 0.6 

(Honestly: It's hard to come up with minus when you are so close to the project but I feel that also makes me capable of poining out pluses... so, please suggest edits to insert in some minus points)