There’s a long chain of 4 questions on this subject ending in a comparison between C# and Javascript while leaving Boo aside. None of them answered this question, and I believe most of them are outdated.
Few years ago, the so called UnityScript was most used, maybe because it was the only one found on the docs. Nowadays it is C#, hands down, the preferred option. It is consistent with .NET and thus the examples and community support we can find on the net is huge. Plus it seems like it can do stuff that JavaScript can’t, while keeping everything less buggy. So, that alone was good reason for many people to drop UnityScript (I keep interchanging its name because it is still ambiguous).
To me it seems like, today, JavaScript is just a bad choice for beginning a project.
And how about Boo? If someone was to begin a new project from scratch is there any reason, other than the community, to forget Boo? Why does it even exist then? Above all, why C-sharp is so much more powerful than Javascript (at least in Unity) and is it the same against Boo?!