Somewhat haphazardly: * You don't have the C# baggage * You have a modern module system, which is only paralleled in Standard ML. This is very important for l

Somewhat haphazardly: * You don't have the C# baggage * You have a modern module system, which is only paralleled in Standard ML. This is very important for large developments where the need to split your code base into manageble chunks is extremely important. * The sequential code generator is very good. * Compilation times are fast. Not Go-fast, but reasonably fast. Building OCaml itself with OCaml can be done in around 1 minute on a fast machine. * The language is strict! This makes some gotchas w.r.t memory behaviour much easier to reason about, and is a definining distinction towards Haskell * The language is rather small in the core. In contrast to Scala. * The Garbage Collector is state of the art. It is fast. It has small pause times. It doesn't overuse memory. * The language is mature, which Rust isnt'. When Janes Street started, Rust did not even exist.