It’s not as great as it sounds. You write enough system software in functional languages and you realize you just traded one set of headaches for a different but equally infuriating set, and that most headaches are sociological aspects of teams writing code, not just isolated gifted engineers separately writing perfectly idiomatic functional programming designs.

Jane Street also has one of the absolute worst reputations for brutal hazing-style trivia interviews. Round after round with no official timeline given. Nonsense word problems that have no bearing to “how someone thinks.” I think it’s short-sighted when people don’t stop to ask, if a company believes it is entitled to treat candidates that way when evaluating them, what else might it mean about internal culture?

While I think Jane Street is probably an above average employer, I also think people get carried away glorifying them. It’s great pay and benefits, occasionally interesting problems, and all the same headaches as working anywhere else.