It may sound strange but the advantage is that it's a fun language. It looks nice when you read the code and you can get lots of stuff done in very few lines of code.
The main appeal for most is obviously the existance of the Rails framework which lets you build webapps fairly quickly and in a nice and sane way (imo) but similar frameworks exist for Java, PHP, Python etc.
Ruby the language itself is pretty nifty though, everything is an object, classes are always open, metaprogramming is easy, closures are uncomplicated and make life easy, duck typed, mixins instead of multiple inheritance, (almost) functional programming is possible and used
It's been buzzing for a couple of years now. Twitter uses it, so do some other projects you'll know if that's your domain (metasploit for example)
Edit: Just saw this quote in 7 languages in 7 weeks: "If you think of other C-based languages such as JAVA as old draconian British nannies...Ruby is like Mary Poppins"
I like it
Last edited by clowntable; 03-06-2012 at 11:28 AM.