For most things it was fine. I had some issues installing Erlang via asdf. I wasn’t sure if that was due to running the beta. But when trying to install via Homebrew, there was a warning about Big Sur not being supported and that I would have build failures.
That being said Erlang and Elixir seem to run just fine 
It’s not my main dev machine. I could have avoided issues due to not using it as heavily.