I'm not well versed on modern pg for this use, but when I managed a Solr instance ~5 years ago, it was the ranking of the results that was the killer feature. Finding results fast most systems can do. Knowing which results to present is harder.

Our case was a domain specific knowledge base, with certain terms occurring often in many articles. Searching for a term could bring up thousands of results, but few of them were actually relevant to show in context of the search, they just happened to use the term.