From what I've seen of Rust though it adds its own brand of complexity due to its basic requirement for maximal efficiency which precludes having a garbage coll

From what I've seen of Rust though it adds its own brand of complexity due to its basic requirement for maximal efficiency which precludes having a garbage collector. I don't think I would want to use Rust unless I really needed a language with near optimal performance. OCaml on the other hand seems suitable for programs where correctness is important but performance isn't the driving concern. At least I'm considering using it for that type of application, though I'm not yet a serious OCaml programmer (still working my way through this course actually).