Ocaml and Haskell are both good languages. Haskell probably has a bigger community and more momentum at this point. I switched from Ocaml to Haskell long ago

Ocaml and Haskell are both good languages. Haskell probably has a bigger community and more momentum at this point. I switched from Ocaml to Haskell long ago because I wanted parallelism. The implementation philosophy of the two languages is pretty different, despite being superficially similar in terms of syntax. Ocaml is pretty predictable -- you can look at code and have a pretty good idea of what kind of code the compiler is going to generate. Haskell is a lot more opaque. Between laziness and a more rigid type system, ghc can do some pretty crazy code transformations. In general, this is a good thing, but it can make performance questions harder to figure out. I think that Ocaml is easier to learn, but Haskell is more fun, and I've learned more from using it.