Meh, I'm not sure where I stand on this argument - I've recently been having an affair with Haskell and I prefer the Haskell Way. The way Haskell models I/O seems confusing at first but monads make the whole thing more manageable than any language I've ever used.

"More control over state" makes me feel funny inside; if you haven't actually used Haskell then you would probably see that pretty much every language right now is immature in comparison to Haskell when it comes to "control over state".

I also think mutability makes reasoning about large concurrent and/or parallel programs much more difficult.