Just to kind of chime in with respect to the whole “C# will be slow” FUD: .NET/Mono in general is going to be less performant than C++, but for reasons of scripting typically you don’t actually care about the performance impact so long as you’re not doing anything that’s particularly intensive (like physics simulations). You’re typically not going to be pushing it hard enough that the VM’s JIT will harm performance in a way that you will actually notice.
Besides, if you really want to complain about performance of scripting systems, let’s all think back to the days of UnrealScript or even interpreted scripting languages! Ah, those were the good ole’ days.