I have only two nitpicks with my M1 Mac: (1) it's not a good fit for virtualization (whether docker or VMs) -- but this limitation is well-known, and (2) the only time I see slowdowns is occasionally when opening a new tab in Safari -- even when almost nothing else is running. The second one also happened on my Intel Mac, just a bummer that the issue hasn't magically gone away.
Beyond that, I wouldn't change a thing about this machine. Very easy to recommend!