I have very fond memories of OCaml. It was OCaml that introduced me to functional programming, way back in 2000 in my freshman year at the uni. I'm a Lisper/Clojurian these days, but I think warmly of OCaml's type system, the speed, the self-containedness of the distribution, and the fact that getting the code to compile tends to mean getting it to actually work.
My #1 gripe with OCaml is the fact that its strings are composed of single-byte characters. I know there's Camomile, but not having it as part of the language core creates a sense of disintegration akin to PHP and Python 2.
There's also this: http://www.podval.org/~sds/ocaml-sucks.html which I mostly agree with.
But, all in all, OCaml rocks.