I've seen the opposite, and have seen some pretty big fast large professional systems being built in it. Admittedly most of them are closed source, and the comm

I've seen the opposite, and have seen some pretty big fast large professional systems being built in it. Admittedly most of them are closed source, and the community contribution allowed to be made is small. Most of the developers using it normally just market themselves as C# developers when they change job because of some of the above opinions they see online. Have seen speed comparisons compared to other similar tiered languages internally where F# shines with less code as well particuarly around math (C# is just starting to catch up here). Even seen dynamic problems solved in it to your point in a professional setting to speed up very often run calculations to a large customer base. However technical capability and efficiency of the tool isn't the only concern picking up the comments in this thread so far. The herd effect sadly can make people nervous creating a barrier for people to try it especially if career is in it. What other people think of it, and their preconceived notion can matter.