A few years back I read that a guy killed a child with his Ferrari: he missed the turn after a strong acceleration (as he left a Ferrari gathering!). And then more recently I read the same type of story, again with a Ferrari and an uncontrolled turn at an intersection.
Well, F# is like a Ferrari (maybe that is what the F stands for ;-) ). It is incredibly more productive than other .net languages; see it as a language with an incredible acceleration. But the caveat is that programming in a functional language is much more of a balancing act, and therefore beware the slippery turns and “intellectual crashes”. This is especially a management and team issue, a language like F# allows you to blend in the same code concepts that can be dealt by your “standard” developer and concepts that take years to master. (It can be even worse than C++ template meta-programming.)
If you were going to set up a taxi company would you buy a fleet of Ferraris if they were available at the same price? Well that is a little bit the same type of question you need to ask yourself when you choose a language like F# or Scala for your team. And it is a tricky question and I would argue that Microsoft is wise not to over market F#.You choose it because you know what it will bring you and you are "old enough" to understand the risks you are taking!