The feature set from an application perspective is killer. I love window functions especially; all sorts of clever things can be done in a single query which would otherwise require painful self-joins or multiple iterated queries and application-side joins in less sophisticated dialects.
My favorite killer feature is jsonb_agg / jsonb_object_agg which let me pull trees of data in a single query without the exponential waste you’s get from cartesian products, and even deliver it to the frontend without needing to assemble the json myself.
