It's faster than MRI. It allows you to write Java instead of C extensions. For developers without a C background, but with a Java or c# background that's pretty

It's faster than MRI. It allows you to write Java instead of C extensions. For developers without a C background, but with a Java or c# background that's pretty huge IMO. Plus instead of running 16 Unicorn workers for an app, eating up over 4GB of memory, I can run one JRuby thread-pooled app, handling many more connections gracefully, with lower memory requirements, fewer database connections and better performance.