I have the first generation of the M1 (M1 Max) and this is the first Apple laptop I own that doesn't seem to hit any thermal or power limit. I do use an app to spin the fans faster when doing something like encoding a blu-ray movie with HandBrake, but it keeps going for hours without any noticeable drop in performance.

If you look at stress tests from a M1 on a Macbook Pro and a M1 on a Mac desktop, performance is similar. There might be a difference on sustained performance on the M1 Air, but that's because it doesn't have any fans.