Opus is now in preview builds behind a flag. Please see https://blogs.windows.com/msedgedev/2016/04/18/webm-vp9-and-opus-support-in-microsoft-edge/Anonymous commented
Opus outperforms every other codec in practically every way relevant. However, vorbis is also good, and is in wide use.
Ultimately, opus will become the defacto audio standard, because of it's superior quality and flexibility. Best to start supporting it now.