Disclaimer: I use Postgres fulltext search in production, very happy with it although maintaining the various triggers and stored procs it requires to work becomes cumbersome whenever you have to write a migration that alters any of them (or that in fact touches any related field, as you may be required to drop and recreate all of the parts in order not to violate referential integrity)
It is certainly nice having not to worry about 1 additional dependency when deploying, though
You CAN score results using setweight, although it's likely not as sophisticated as Elasticsearch's
https://www.postgresql.org/docs/9.1/textsearch-controls.html
Disclaimer: I use Postgres fulltext search in production, very happy with it although maintaining the various triggers and stored procs it requires to work becomes cumbersome whenever you have to write a migration that alters any of them (or that in fact touches any related field, as you may be required to drop and recreate all of the parts in order not to violate referential integrity)
It is certainly nice having not to worry about 1 additional dependency when deploying, though