ATS is interesting. I've seen it used in device drivers and one 8-bit system IIRC. The reason I left it off is that I'm not sure most people can learn how to use it. Whereas, we've taught ALGOL languages, Scheme, and Ocaml to all kinds of people where they're effective enough with types & assertions.

These more mathematical languages have to prove themselves out with real-world examples, algorithms and compiled code, before I recommend them. I'd like to see CompSci keep hammering away at them to find easier and easier ways of learning and using them. Not to mention improve tooling.