My observation is that the ex JS/Ruby/etc devs learning curve's seem to favor F# over C# as it is more like these languages. There's just a lot less to learn, and the coding style (e.g. modules, function first, etc) is more synonymous with langs like JS than heavy OO languages. I've recently inherited a team that moved to .NET from JS, and getting them to try C# has been painful especially when using things like ASP.NET. There's a lot of knowledge I just took for granted - we don't realise how much knowledge is required to use standard Java/C# OO in a production like setting that many dev's stumbled on when they were junior but have long forgotten the learning curve they went through. They tend to be framework heavy/dependent and require much more experience. From patterns (what's a strategy, repository, etc etc), to dep injection frameworks, to which refactoring tools I need, etc, etc - where in F# in my recent experience the experience is more, but still not quite "just code and work it out as you go".
The pit of success favors F# over C# in my experience with these teams especially if you keep it simple with the features used.
My experience has been that F# appeals to coders who are using the .NET platform coming from languages like JS/Go/etc but also has static typing who usually at least in the jobs I've been in are often on a Mac. C# dev's typically come from Java/C# enterprise kind of shops. Not one is better than the other and I will work in whatever space has interesting problems to solve - I think the difference is more cultural than technical.