If you are the real Sven then kudos for signing your name to this comment but I think it looks a bit opportunistic of you to pile on in this context with a recommendation for your language. No language is perfect and xtend itself hasn't even been used in anger yet.
It's like the Kentucky Derby. There's the big 4, scala, clojure, JRuby and groovy, all nice languages. Then there's the little 5: kotlin, ceylon, gosu, fantom, Xtend. Gosu and fantom are worth trying, I just haven't got around to it..