Is there any company / product that uses it? (serious question)
I heard good things about many other "nice" languages, just nobody saw them in the wild, actually doing something useful...
From what I've read it's mostly used in safety-critical applications. The kind where if something is amiss, your plane crashes. It's niche, but it is actually in use. It's not a toy or academic-only programming language, like you seem to be alluding to.
Ada? I've heard that it is very big on safety, and that it is in the C ballpark efficiency-wise.