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.
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.