This is a very interesting list. We built our business around a purpose-built search engine on top of Elasticsearch, and that is giving me some new ideas. Havi

This is a very interesting list. We built our business around a purpose-built search engine on top of Elasticsearch, and that is giving me some new ideas. Having said that: does anyone have recommendations on contenders to Elasticsearch for highly complex data search (that is not e-commerce..)? Getting very tired of their licensing model.