Oo I’m excited for this. The old official language server is fine—it does its job on most of the code bases I’ve worked on, but occasionally I will do something funny that makes the compiler slow down and that pummels the LS performance. I hope this works out some of the kinks that occasionally would make elixir-ls slow.
Nit: there has never been an official LSP implementation until now, only community-authored. Even now no Dashbit employees or language core members are directly involved in this project in an ongoing basis.
IMO that contributes powerfully to the quality of the experiences of using any of the options.