Apache Solr

Rich document handling making it ideal for Enterprise content management Apache Solr is highly configurable, supporting fine grained relevance tuning, custom analyzers, etc Built in faceting empowers dynamic filtering and exploration critical in e-commerce scenarios

It has been widely adopted in a range of popular open source applications, and it is well supported by many backend libraries.

Flexibility, you can configure every component pretty well

Complexity of deployment and setup, including upgrades, requires significant technical skills and planning Resource intensive scaling esp for any mission critical environments Out of the box Solr lags in the native Machine learning support

Complex configuration compared to other search engines without a real difference in outcome, schema management might be less than ideal for many apps; scaling challenges will surface one the app grows. Limited real-time capabilities, and requires Zookeeper to be running

Well, java is eating memory very intensive, so you need big boxes for what you are doing