It's the combination of features which is killer. I don't know of another language that offers all of these: - Expression orientated - Lightweight syntax - E

It's the combination of features which is killer. I don't know of another language that offers all of these: - Expression orientated - Lightweight syntax - Emphasis on immutable data and pure functions - do-notation (in F# these are called Computation Expressions) - Type-safety without too many annotations (global type-inference) - Mainstream ecosystem of libraries (in this case .NET) - Compile to JavaScript