They have different organisation structures, where Alma is a 501c Non-profit and Rocky is a backed by a B-Corp, so in my head I read one of those as a community linux ie. Debian-feeling, and the other aims to make money ie: Ubuntu-feeling. That's an extremely crude interpretation though, both need cash to support themselves, so both need to make money some how.

Day to day they should be by design, interchangeable. Rocky has a nicer logo... This kind of ugly exchange on reddit[0] always sort of soured my impression of Rocky though, didn't really pass the lebowski test.

0. https://www.reddit.com/r/linux/comments/qv6mg2/were_the_alma...

Alma has been faster with releasing updates and security patches from what I’ve seen.

This seems to be true. However, looking at https://rockylinux.org/news/rocky-linux-9-2-ga-release:

9.2 Release for PowerPC (ppc64le) architecture held back

During testing, we discovered an architecture-specific issue on ppc64le systems with the bundled version of Python 3.9. This issue not only prevents installing, but may break existing installations.

This issue is reproducible on CentOS Stream 9 and RHEL 9.2. We have opened a bug report upstream at rhbz#2203919 and are working to fix the issue.

Seems like they hold back releases to do additional testing. In this case, they avoided a bug that was present on RHEL (and presumably AlmaLinux).

regardless of the status of the bugzilla. That _is_ a bug and a regression in RHEL 9.2.

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Last I looked, there was no real difference. I don't know if there would be any politics preventing it, but I would not be too surprised if they merged at some point.