The main thing I found strange about F# was that, having prior familiarity with Ocaml and SML/NJ, was that what F# calls modules are completely unlike the module system of any other ML-inspired language, being instead an adaption of C# classes to serve F#'s namespacing needs. Since the module system is of similar importance to code reuse to Haskell's typeclasses,the relative deficiencies of F#'s module system hurt.
