[math]

I trialed F# a while back. Something I certainly noticed was not having as much help from the IDE (no resharper). The lambda notation also annoyed me (by comparison to C#). Yeah, I know it's no big deal and I understand the trade-offs being made.. but it still annoyed me. Pattern matching is one of the draw cards - but I see that is coming in C# soon.

[edgyswingset]

Did you give F# Power Tools a go? It gives you a lot of what is missing out of the box. It's still not as great as C# IDE support, but for most things it gets the job done.

[MichaelGG]

While this may come across as sour grapes, I find generally I need less IDE help in F#, since I'm not typing as much boilerplate. For instance, almost all type annotations are inferred (20:1 in my own empirical study), so there's a ton of code I simply don't need to type.

In general, I find writing in C#, I'm going to need 50-200% more code for "business logic" type code that doesn't particularly benefit from F#. That is, using F# as a better C#. And this is after C# hacked in async - before that, there's no comparison if you need async style code.

If C# added pattern matching, tuples, active patterns, type inference, everything-as-an-expression, nesting, more comprehensions, etc. etc., then yes, C# would be competitive. And with all the resources C# gets, the IDE would be far better than F#, sure.

[CmonDev]

Sadly F# had inherited all the OCAML luggage, including the arcane academic ML syntax.