I think it hits a sweet spot. Not as boring as Go, not as obstinate and distracting as Rust ("I'm sorry, Dave"), not purely functional for those who don't want to go all the way in that direction. I expect people who try those languages and decide "not quite" might try OCaml and find it more flexible and elegant. It's appearing more often in the "who's hiring" posts. There are the characteristics such as compilation speed vs others which could do with being, ahem, compiled into a post somewhere, if not already.
> not purely functional for those who don't want to go all the way in that direction
That's why I first loved it. I liked what I knew of Haskell but was skeptical of the Monadic IO system (I've since warmed to the idea). OCaml was in a perfect sweet spot in my opinion.
Also it feels a bit less abstract in some difficult to define way - I don't think Monads really clicked for me until I was using Options in OCaml.
I'll also second the opinion that as a _language_ OCaml is more ergonomic than Rust. However, I find that Rust is more _community ergonomic_ - it's easier to find libraries and contribute to them. Related to that - the build process is just spot-on. With OCaml, I found myself tripping over obscure errors in my build process about every month or so.
For me, OCaml is a bit like the one that got away.
But I'm excited about the momentum behind the Reason project!
