I use it as a hobbyist, it's much more pleasant to program in than C# once you get over the minimal hump of thinking more functionally than you would in C#/Java/etc. It has a great type system and the available tooling is pretty nice (powerful tools for data, parsing, etc exist for it as with many other functional or math-oriented languages). The annoying bit is that MS doesn't seem to care that much about it despite it being much sleeker, flexible, and terse than C# or VB, and thus it tends to sit unused despite all its niceties.