I tried out Purescript for a project and didn't think it's ready for production... Generic encoding/decoding was painful, the lack of good dependency management was painful, too many things were either missing or immature. I hope in a year or two the story will be better.
Nope, they break things all the time. Or at least, they did one major break earlier this year. "Production ready" is different from "should I use this ever at all though."
Doesn't really answer the question I posed though.