I was developing a small game for like three years (part-time) in Scala, been toying with Haskell for like 5 (only on weekends for few hours, I would still rate myself as beginner or mildly advanced user). Now I am starting (few months of part-time in) working on a game in Unity, so I am using (older) C#. I would not rate C# extremely high, compared to Scala or Haskell, it lacks a lot - doesn't have easy immutable data structures, it has collections library designed for special people (read people who didn't work in any other language and didn't study at university, only worked with relational DB), missing Option/Maybe, interfaces are inferior to traits from Scala, a lot of syntax (Linq) seems cobbled on without much thought, a lot of features seem not to be orthogonal (I think syntax-wise C# is much more complicated than Scala, yet Scala is more powerful [the typesystem is much better], cleaner and succinct), required "virtual" modifier seems archaic and too low level, type inference is quite weak (weaker than Scala, and Scala is not that great in it in a first place), functions/lambdas feel like second class citizens (again weird naming strikes, often incapable of inferring types which leads to very long types), no pattern matching (I think this omission is fixed in newer version), its multiplatform story is a lot to be desired (yes, core part is open-source and multiplatform, but many things are MS-world only, so unless you are targeting only Windows or wanting to work in Unity, there are much better options elsewhere).
TLDR: I am not a fan of C# and find many its parts infuriating. You can get work done in it, but if you ever tasted above average language then you probably will be disappointed. If you ever worked only in mainstream ones, like Java, JavaScript or PHP without ever doing even basic FP, you might appreciate C# (definitely more than me).
I was developing a small game for like three years (part-time) in Scala, been toying with Haskell for like 5 (only on weekends for few hours, I would still rate myself as beginner or mildly advanced user). Now I am starting (few months of part-time in) working on a game in Unity, so I am using (older) C#. I would not rate C# extremely high, compared to Scala or Haskell, it lacks a lot - doesn't have easy immutable data structures, it has collections library designed for special people (read people who didn't work in any other language and didn't study at university, only worked with relational DB), missing Option/Maybe, interfaces are inferior to traits from Scala, a lot of syntax (Linq) seems cobbled on without much thought, a lot of features seem not to be orthogonal (I think syntax-wise C# is much more complicated than Scala, yet Scala is more powerful [the typesystem is much better], cleaner and succinct), required "virtual" modifier seems archaic and too low level, type inference is quite weak (weaker than Scala, and Scala is not that great in it in a first place), functions/lambdas feel like second class citizens (again weird naming strikes, often incapable of inferring types which leads to very long types), no pattern matching (I think this omission is fixed in newer version), its multiplatform story is a lot to be desired (yes, core part is open-source and multiplatform, but many things are MS-world only, so unless you are targeting only Windows or wanting to work in Unity, there are much better options elsewhere).
TLDR: I am not a fan of C# and find many its parts infuriating. You can get work done in it, but if you ever tasted above average language then you probably will be disappointed. If you ever worked only in mainstream ones, like Java, JavaScript or PHP without ever doing even basic FP, you might appreciate C# (definitely more than me).