I worked on a huge (12TB) bioinformatic project which was using PostgreSQL full text search as a primary component. One would compare with Solr which also was looked at as a possible replacement.

Solr had more functionality (largely by being able to throw more nodes at the problem), but for our purposes, PostgreSQL's fts was certainly good enough. There were a few cases where we had to be careful so the full text index would be used (because data distribution did not always match the planner's assumptions) but on the whole it worked very well.