I think this is a pretty good overview of the potential concerns with BlueSky.
My quibble with Cory implying that moving instances is almost free, is that that while you can move server to server pretty seamlessly on fedi/AP, currently you lose your entire posting history.
I know there have been projects to allow full migration but they’re (so far) not really there.
(ht: @mackuba over on BlueSky (ironically) for pointing out this article) https://mamot.fr/@pluralistic/113413507213509943