Interestingly, I found F# to be far less intuitive than Scala. I came from a background where I had done functional in Scheme, SML, and a little OCaml, but most of my time was spent coding OO in Java and C++. My problem with F# was that it wanted to be a functional language in an OO framework (.NET). The result was that some operations were function calls and others were method invocations, and I generally couldn’t see any good reason why one was chosen over the other, so you had to memorize which things were which. I’m pretty sure that the difference was historical and not really meaningful. The things that came from OCaml were function calls because that was how it was done there. The things that came from .NET were methods for a similar reason, but the end result was not a smooth blending of the two paradigms.

I find that Scala’s simple decision to make functions simply be objects with apply methods led to a much more uniform syntax and created libraries that were generally more coherent.