I used it for a while a few years ago. Like O'Caml or Haskel , F# is a language that forces you think through your problem up front. For example you must get your types exactly right before the program compiles. In return, you get fewer runtime errors, e.g. fewer null pointer exceptions.

I stopped using it when I changed jobs and left the Windows platform.

I don't really miss F#. It was fun to learn and use, but wasn't helping me write better programs quicker than C# or Python.