I am using Docker Preview 3.1.0(60984) with the Air, and its super fast. A build process that usually takes 5 seconds on a maxed out intel MacBook Pro takes a few milliseconds on M1 Air (16GB).
Docker crashed once or twice within the last month but nothing major, just restarted the Docker engine and it was fine.
edit YMMV. I use Docker with a NodeJS stack.