For me it's exactly the same. I use groovy to prototype small functionalities for the big Java application that I'm working on, but I will never consider to use

For me it's exactly the same. I use groovy to prototype small functionalities for the big Java application that I'm working on, but I will never consider to use it to build a full non toy-size application. I use Python and Ruby for small scripts and I can't really see how people would ever want to use it for big applications. The lack of static types is the problem. For this reason I don't agree with the author when he says that OO is the problem. While loving functional programming I think that a well executed application written in a OO language with static typing is not a nightmare to maintain. You can write code impossible to maintain in Haskell and you can write pretty nice maintainable code in C#. Probably I prefer the nice balance that you can strike with F#, even with the flaws that it has. (Typeclasses anyone?)