When comparing ElixirScript vs OCaml, the Slant community recommends OCaml for most people. In the question“What is the best programming language to learn for backend developers?” OCaml is ranked 14th while ElixirScript is ranked 25th. The most important reason people chose OCaml is:
Functional programming is based on the lambda calculus. OCaml is in its functional parts almost pure lambda calculus, in a very practical manner: useful for many daily programming tasks. The acitve development makes improvements to the type system like generalized algebraic data types (GADT) or polymorphic variants, so when learning this language you get at once a down to earth usable compiler and advanced abstraction features.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Clear syntax
Uncluttered, yet unambiguous syntax

Pro Excellent community
The Elixir community has proved to be welcoming and very supportive.
Pro Great for concurrency
Leverages the existing Erlang BEAM VM
Pro More familiar syntax
All of the benefits of Erlang; without as steep a learning curve of prolog based syntax. Elixir is heavily inspired by Ruby's syntax which many people love.
Pro Great documentation
Elixir's documentation is very good. It covers everything and always helps solving any problem you may have. It's also always available from the terminal.
Pro Actively-developed functional programming language at the forefront of research
Functional programming is based on the lambda calculus. OCaml is in its functional parts almost pure lambda calculus, in a very practical manner: useful for many daily programming tasks. The acitve development makes improvements to the type system like generalized algebraic data types (GADT) or polymorphic variants, so when learning this language you get at once a down to earth usable compiler and advanced abstraction features.
Pro Encourages functional style
It steers you towards a functional style, but doesn't bother you with purity and "monads everywhere" like other languages, such as Haskell.
Pro No windows!
Strong focus on *nix systems, lacking native support for MS Windows
Lacks native support for Windows systems.
Pro Sophisticated and easy-to-use package manager
OPAM is a package manager for OCaml, which is really easy to use, just like npm. It creates a .opam folder in home directory.
The documentation is great as well, and you can switch between multiple versions of OCaml for each project. You can also package your project and publish it on OPAM repositories, even if the dependencies do not exists on OPAM.
Pro One of the best for writing compilers
OCaml is compiled to native binary, so it's amazingly fast. Being a member of ML-family languages, it has expressive syntax for trees, and has great LLVM support.
Pro Stable syntax
The syntax is consistent, some syntaxic sugar but at a reasonable level, so reading code of others isn't too much confusing.
Pro Strong editor integration
The merlin
editor tool provides all you need to develop OCaml in your favourite editor.
Cons
Con Strong focus on *nix systems, lacking native support for MS Windows
Lacks native support for Windows systems.
