I'm a big fan of F# as well. I haven't tried it outside of windows, on mono. I've always wondered how well supported mono was and what the library ecosystem was like (I could just google that, and probably will)

Any personal experience with it?

Right now I'm diving into haskell, partly because I want a static, type-inferred, functional language on linux (my home platform of choice) and partly because I like the idea of using a language that has really pure (functionally and generally) ideas it's trying to implement. Digging it a lot so far as well.