OK, I'm curious now. Wikipedia says[1] the reference implementation is open-source and cross-platform, which is great, but I never hear of anyone talking about F# outside the Microsoft world.
The compiler has to be compiled from source[2] on Ubuntu, which seems to suggest hardly anyone is using it.
Would there be any compelling reason to use F# if you're not working in a primarily Microsoft environment? What does the language itself offer over Ocaml or Haskell?
From what I understand F# works on mono and the F# MS team actually puts in effort to make sure it does. Though for whatever reason mono just isn't that good at running F# code. Maybe it is a weak GC or lack of ability to optimize the code patterns F# produces, I don't know. It is slower than F# on CLR.
Given that, library access and ability to thread are the two big things it is going to have over Ocaml. Cleaner syntax when compared to Ocaml too. Haskell, not much.
Being a Microsoft language helps smuggle it into the work environment of the enterprise.
It has become my scripting language for Windows tasks.