I've been using it a lot, and I really love it. It's the only language I've used in which I found static types to be worth it (I don't count C, as its type system is badly broken, and iss only there to counter some of the language's runtime limitations).
If your problem can be presented as advanced data structures, it's really the right tool for the job. Unless if your problem is purely functional, then maybe in Haskell would do better, but we're talking about a pretty narrow niche.
When you design an application, you can generally shift complexity from the algorithm to the structuring of data, and vice versa. It's better to put complexity into data, as they're easier to debug, and that's even much truer in OCaml.
There's one very cool feature in Haskell that ought to make it into OCaml, though: classes (which are almost unrelated to the homonym OO concept).
If your problem can be presented as advanced data structures, it's really the right tool for the job. Unless if your problem is purely functional, then maybe in Haskell would do better, but we're talking about a pretty narrow niche.
When you design an application, you can generally shift complexity from the algorithm to the structuring of data, and vice versa. It's better to put complexity into data, as they're easier to debug, and that's even much truer in OCaml.
There's one very cool feature in Haskell that ought to make it into OCaml, though: classes (which are almost unrelated to the homonym OO concept).