> First, "functional" isn't an advantage.. I mean, the advantage of functional code might be easier maintenance, concise code, easier to concurrence etc..

Those are all good reasons why functional programming is an advantage. I guess you object to my grouping of all these under the "functional" umbrella term.

> In my opinion, the advantage of clojure by comparing it with Ruby are: - You get the best of Java (lots of library, OO)

I mention this as well, but that's not really an advantage over Ruby. JRuby gives you access to all the Java libraries you want.