This will be related to my experience as someone who has used both on the same hardware, but I have contributed to Bluefin/Aurora/Bazzite previously, so please keep that in mind.
I would rather give an objective difference between the two and not what you should personally use because I find both to be great operating systems, and openSUSE Aeon/Kalpa is extremely underrated in the Linux community and I think deserves more public praise because, in my opinion, it solves all of the issues I’ve had with openSUSE Tumbleweed, which I also used to daily drive, in terms of stability.
openSUSE Aeon:
- rolling release (like openSUSE Tumbleweed with newer package upgrades daily)
- btrfs snapshots for rollbacks / system updates
- minimal in comparison to Bluefin (not as many pre-installed GUI applications)
Bluefin:
- default channel is a fedora release behind, and even the
:latestchannel does not compare to openSUSE’s rolling package update cycle - Uses libostree for system updates and rollbacks
- OS size is larger in comparison to openSUSE Aeon
There are other technical differences, and I encourage you to try it in a VM, research openSUSE Aeon, or get involved with their community too.
Both Bluefin and openSUSE Aeon are intended for “lazy developers” (as openSUSE puts it) and the casual end-user who wants their PC automatically updated while having a focus on both Flatpak and Distrobox containers for obtaining software. openSUSE Aeon was already released to the public before Bluefin was, and there was a lot of inspiration on the out of the box experience from openSUSE in Universal Blue.
Similar to what I said in the Nobara vs. Bazzite thread, open source is all about having cooperation, and both openSUSE Aeon and Bluefin users will both be using nearly identical software stack like Flatpak and Distrobox containers, so using either will benefit the other anyways in a sense.