[bad_user]

Having both Ocaml and F# descending from ML doesn't say much really, other than both implementing Hindley–Milner type inference and sharing some syntax. They are very different languages.

For example Ocaml has functors, polymorphic variants and row polymorphism, versus F# which has .NET"s OOP and subtyping. F# as a language feels to me more limiting.

I won't comment on the runtimes / environments, as they have pros and cons, but there's something odd about F# to Javascript compilers. There's WebSharper and FunScript and now Fable. I don't understand why the community can't get behind a single one, because neither of them is popular enough to have reached critical mass. Take a look at WebSharper's commit activity for the past year and compare with Scala.js or with ClojureScript. And note I'm not saying anything about its technical merits.

Whereas for FunScript and Fable, well FunScript is probably going to die and neither of them seem to cope with "isomorphic" libraries.

[junkyarddog]

There's more to F# then HM type inference plus ".NET's OOP and subtyping". OOP and subtyping are rarely used. While it lacks some of OCaml's powerful features it shares many core features such as algebraic data types, exhaustive pattern matching, immutability by default, Option types and so on. It's also arguably easier to read with it's white space significance and not needing the rather distracting "in" keyword.

Having the vast .NET library is a big plus for the language, of which OCaml has no equivalent. Other great features of F# are type providers, straightforward multi-core programming and units of measure, which I don't believe have OCaml equivalents.