Well, Java is just a pain in the arse to setup and configure. And PHP lacks the same sorts of tools you can get with the Ruby community.

Not to mention PHP only really started making an attempt at OOP with PHP 5, and Ruby was designed from the onset to be OOP. Everything in Ruby is an object, so you can do some really neat stuff like 1.to_s to turn an Integer into a String. Add Ruby's cleanliness and readability to the mix, and it's a standout winner over PHP.