Having developed Haskell professionally for many years, I've spent the last two years programming OCaml professionally. I've been really enjoying the OCaml tooling: dune, Merlin and ocamlformat work extremely well for me. Dune especially is packed full of features, for example a file-watch mode for tests. Merlin doesn't choke on large codebases like some of the Haskell tooling did and ocamlformat works better than any code formatter I have ever used. The tooling is so good, I can forgive the rather minimal standard library. OCaml is also very good regarding backwards compatibility, new releases don't break our builds.