* The newer version of Docker+BulidKit supports bind-mounts/caching/secrets/memory filesystem etc. we used it to significantly speed up builds. You could probably find a way in buildah to achieve the same things, but it's not standard.

* Parallel builds - Docker+BulidKit builds Dockerfile in parallel, in podman things run serially. The combination of caching and parallel builds and Docker being faster even for single-threaded builds, Docker builds ended up an order of magnitude faster than the Podman ones.

* Buggy caching - There were a lot of caching bugs (randomly rebuilding when nothing changed, and reusing cached layers when files have changed). These issues are supposedly fixed, but I've lost trust in the Dockerfile builds.

* Various bugs when used as a drop-in replacement for Docker.

* Recurring issues on Ubuntu. It seemed all the developers were on Fedora/RHEL, and there were recurring issues with the Ubuntu builds. Things might be better now.

* non-root containers require editing /etc/subuid, which you can't do unless you have root access.

More information about the new BuildKit features in Docker:

https://pythonspeed.com/articles/docker-buildkit/