I've actually tried both Postgres FTS and Elasticsearch(in conjunction with a Postgres DB) and found Elasticsearch easier for search. It's much more robust - for my specific case I needed a bunch of Japanese text to be searchable alongside english text; Postgres has very poor support for this - and its API is excellent and its very quick and painless to set up(documentation is not stellar though). You don't have to worry about things like vectors or indices with ES, you can just put the data in and it will be easily searchable, and it's miles more efficient when searching across large data sets. It Java-based so it is a pretty big resource hog though, so I can see the advantage of someone who just needed very lightweight search for their project using tsearch.