I hope the author will check out RWX -- they say they've checked out most CI systems, but I don't think they've tried us out yet. We have everything they praise Buildkite for, except for managing your own compute (and that's coming, soon!). But we also built our own container execution model with CI specifically in mind. We've seen one too many Buildkite pipelines that have a 10 minute Docker build up front (!) and then have to pull a huge docker container across 40 parallel steps, and the overhead is enormous.