I use F# every day, both in my open source and professional work. Love seeing the language continue to improve without going off the rails! I'm looking forward to using the "and!" computations in this release in particular (though I swear they'd already been released).
Edit: oh this post is from November! That's why I thought I'd read about those computations before.
I wish SML had a community like F#
I use OCaml, occasionally, especially for data/transpiler work. I've always wanted to try F#, but it being .NET sort of scares me away. I've always sort of admired the pragmatic beauty of the OCaml ecosystem--at least as much as one can call an ML-derivative 'pragmatic'--though I don't get that same feeling from F#.
Task expressions look neat though, and might give me a reason to try.