When I think of OCaml, the concepts that come to mind are brilliant French computer scientists and hedge funds. A practical Haskell. When I think of F#, I think of... .NET, bright enterprise programmers who want to work with a tolerable language, and that's about it. If forced to name a user of it, I'd say "uhh, no idea... Maybe Stack Overflow?"

(That's entirely aside from the relative merits of both languages, which are leaps and bounds ahead of both most OOP and functional languages.)