Dear camlers,
   I have done some work to  improve omake available here:  https://github.com/bobzhang/omake-fork/tree/work
   Before deciding spending some time in improving omake, I have tried various build systems.   

  1. ocamlbuild
      ocamlbuild is really nice for small to medium projects and I have used it pervasively in my personal projects and corporation projects. It works pretty well in most cases.
     There are mainly three drawbacks:
      a. Easy things hard to do.
          Even for some very trivial things, if you don't write myocamlbuild.m for a long time, you have to google ocamlbuild API and figure it out how to do it correctly.
     b. Error messages hard to understand
         It's cool that ocamlbuild detect dependencies dynamically, when it does not work out, in general, I would turn on -verbose and search which part goes wrong.
     c. no parallellism
        This is fatal and main reason that I gave it up
   2. ocp-build
      I tried it for my hobby project, it's not close to maturity yet.
   3. jenga
      Jenga looks promising, but I don't think it would be usable inside our company, the dependency is huge, more importantly, its dependency chain includes Camlp4 which we can not rely on. Also, looking at the examples, it is quite verbose even for trivial projects.

   omake has its own drawbacks as well, for example, the language is overly complex and error message is hard to understand(still better than ocamlbuild), startup speed is slow, no easy FFI interface to write rules in OCaml language itself, but that's all we can find a way to fix.