Performance has been and continues to be a big focus area for Teams. One main area we have made improvements in is responsiveness for the most frequent user actions of switching between Chat, Channel, and Activity. We are also focused on reducing resource consumption and application load time. More improvements are on the way.
We are getting closer… the team is almost ready to rollout MacOS notification support internally for testing – we hope to have it to the public by the end of this quarter.
I'll further this to say "native notifications across platforms". This is a super annoying issue on both OSX and Win10 since the Teams client doesn't use native notifications in either version.
Because of this, they overlap with the placement of native Win10 notifications and don't adhere to Quiet Hours (or DnN on OSX).