In terms of polish and app/dev ecosystem, I feel SailfishOS still rules, but it's getting harder to justify using/development, with it's increasing divergence from upstream.
FuriOS (and its base Droidian) are at a better stage of development for devices made to run Android using the old Android Linux kernel, whereas postmarketOS is better for devices made specifically for Linux, like the Liberty Phone, Pinephone, etc. Droidian will not even work on them.