And yes, somehow the OCaml guys have managed to implement generics and AOT compilation to optimized machine code long before the .NET framework existed, but now this is something "truly hard" on .NET.
The syntax is quirky, there's a bunch of legacy baggage (does anyone use the OO stuff?), there's no SMP support (though I know this is being worked on), the toolchain feels antiquated (the REPL still, to this day, doesn't come with Readline support built in; rlwrap is required!), etc. Not to mention the lack of modern libraries, frameworks, package management, etc.
Reason and BuckleScript are nice, though. Reason cleans up a lot of my complaints, while still not being quite as elegant as F#. But there's this sense that nobody really wants to make any groundbreaking effort here; there doesn't seem to be any push to make Reason a first-class, new syntax for OCaml, so it's stuck being a web-oriented veener for new users, while old "industrial" users like Jane Street are content to continue with their thing.
OCaml's object and class systems are excellent; I prefer them to just about anything else. They rarely get used for the simple reason that algebraic types, functors, and first-class modules are better suited to modeling almost any kind of domain logic.
Also, I like OCaml's extremely simple and direct syntax. I'm fine with F#'s implicit `in`, though it requires whitespace-sensitivity. I think ReasonML went in the wrong direction, cluttering it up with curly braces and ubiquitous tuple-like syntax for function arguments.
OCaml actually has excellent tooling — among the best — and some (but not many) great libraries. What it lacks most is great documentation...
I don't think even the core OCaml devs would claim this. Rust (and Java and Microsoft) toolchains are examples of excellent tooling. OCaml, not so much.
That said, the tooling situation today in OCaml is much better than it was a few years ago, which is real progress.
What it's sorely missing right now is higher quality documentation output. Currently, it's hard to navigate the generated documentation (e.g., no search bar), it's not held in a centralized online location, and it doesn't do a great job dealing with complex module/functor hierarchies (especially in the presence of destructive substitution).
Unfortunately, much of what I described above doesn't come out of the box. To fix this, the OCaml community is seeking to emulate Rust's cargo tool via the development of the ocaml-platform: http://ocamllabs.io/doc/platform.html
An aside: I didn't know Java had good tooling. I know it recently gained a good REPL. But what is the official package manager, and where is the centralized repository for packages?