In addition to other points in siblings, transactional ddl statemwnts and efficient alter table add column statements for null default columns.

Postgis, pg_trgm,and pg-routing are amazing plugins. (Postgis is a standard compliant gis extension, pg trgm adds trigram indexing, pgrouting does graph (node-vertex) searching) More complex index types out of the box. My experience is that Pg's full text search, out of the box, is better, easier to make better, and easier to index.