Regardless of which language is better the size of the C# talent pool over the F# one would be enough of a reason for project requiring a decently sized team.

A functional language is not going to be appropriate for everything, and in F# you have to explicitly do extra work to have mutable state. If you're doing a UI or game C# will probably be a more natural fit. C# probably works better with Intellisense because the types are basically always explicit, whereas you can use type inference in F#. C-style syntax is a lot more comfortable for a lot of people.

> If you're in .NET land I have no idea why you would chose C# over F#.

One of our reasons: The pool of (good) developers who can write C# is already pretty small in our little city. My company has enough trouble finding developers qualified to play with C#. If we switched to F#, our already-slow hiring would grind to a halt.

Familiar and comfortable syntax with C/C++/Obj-C/Java/Swift/Javascript/Typscript/Scala/etc... It's a procedural language, yet adopts functional elements. And the pool of developers is several orders of magnitude more. Your comment reeks of fanboyism.

C# tooling is better

Definitely, why in the hell do my files need to be arranged in compile order, that's absurd.