[Supabase cofounder]

Firebase is really only bad if/when you decide to move - usually because of scaling/performance issues. For example, you can only query one document per-second. Once you decide to migrate away, it's very painful - but the truth is all migrations are painful.

This is one of the reasons we chose postgres. If you want to migrate away, you can just "take your database" with you. PG can scale with the best of them.

Edit: I said "you can only query one document per-second" but this is supposed to be "you can only query each document once per-second". Sorry!