> can someone familiar with both Elixir and Erlang explain what Elixir provides in comparison to Erlang.
The syntax is nicer, but that's just a bonus. The real game-changer to me about Elixir vs Erlang is its macro system. This gives you runtime code execution and runtime code generation, similar to what makes LISP to powerful.
There's a large amount of boilerplate involved in creating an OTP server, as you know if you've done any Erlang. Elixir's macro capabilities completely eliminate all the boilerplate.
The source to both Elixir and Phoenix are quite elegant and educational to browse, and demonstrate this runtime code generation aspect very well. It's straightforward in Elixir to introspect code, represent that code as data structures, manipulate those data structures, then generate or execute that code, as you can in LISP.
Elixir also gives a number of excellent tools that streamline the support process over vanilla Erlang. For example, Elixir's runtime tooling automatically manages dependencies for you (similar to node's npm), and automatically maintains the application string that you need to provide for all OTP applications. It also has improved capabilities for testing, which are also made possible by the amazing macro generation capabilities.
> I'm looking into using Erlang for a new project that requires extensive scaling and concurrency and am coming from a functional background so may be more comfortable with the traditional Erlang syntax
Elixir's syntax is still just as functional. They support a regular if statement, unlike Erlang, but generally it's just as functional as Erlang. Elixir eliminates a number of needless chores from Erlang, such as having to end some lines of code with a comma, and others with a period, and then shuffling punctuation around whenever you add or remove lines of code. That's a task I used to do literally a hundred times a day in Erlang that I don't have to do at all any more.