A few mentioned in this article are true modules and polymorphic variants. Both can be partially modeled in Haskell, but it's tougher. I feel that almost nobody would disagree that these are advantages of OCaml.
Most people also suggest that strict evaluation and impurity are good traits of OCaml. This is more a contested point, however, as lazy evaluation and strict evaluation are more like duals than one being definitely better than the other. Furthermore, unrestricted side effects are a major tradeoff between convenience and safety—it's up to your use case to decide what's best.
Finally, OCaml obviously has an "O"bject system in it. My understanding is that serious OCamlers shy away from it for reasons of complexity and low value. The major stuff is provided by the module system and doesn't have anything particularly "object" about it.
Most people also suggest that strict evaluation and impurity are good traits of OCaml. This is more a contested point, however, as lazy evaluation and strict evaluation are more like duals than one being definitely better than the other. Furthermore, unrestricted side effects are a major tradeoff between convenience and safety—it's up to your use case to decide what's best.
Finally, OCaml obviously has an "O"bject system in it. My understanding is that serious OCamlers shy away from it for reasons of complexity and low value. The major stuff is provided by the module system and doesn't have anything particularly "object" about it.