It's been years, but I really liked emacs' tuareg mode http://tuareg.forge.ocamlcore.org/
But if you're afraid of emacs, then it's not the right tool.
I specially like the shell integration and the possibility to "throw" a function you're developping in the shell and then test it.
EDIT For the subquestion, OCaml seems dead, and it's a pitty. However you cannot compare it with ruby/python. I'd say it's main competitor is Haskell which seems to be growing in popularity.