Mandatory clarification: there is no “best” tool in almost any area. You pick what you like for the functionality that you require and are willing to give up other functionality you don’t deem important.
I personally can’t stand Visual Studio Code but many people like it, plus the active plugin system allows the community to improve the IDE constantly. So it’s very likely a safe bet for you.
I went for Emacs with a language server and a few addons for project management, searching inside files etc. I don’t care about auto-generated typespecs and semi-automated refactoring so I don’t miss VS Code.
We also have people here who use VIM + addons for Elixir development.
