I think what made ES particularly attractive in the beginning was - Easier (linux-pks) install and setup a small cluster - "Just throw some data at it" - JSO

I think what made ES particularly attractive in the beginning was - Easier (linux-pks) install and setup a small cluster - "Just throw some data at it" - JSON and pure REST While ES is still more compact and faster/easier to install, Solr has of course grown up with robust SolrCloud scaling, start scripts, schemaless mode and all the config APIs. And I think the change of mindset from files to APIs is crucial. Your search engine should be like a DB, just install it and then start using it from a client. Your schema stays close to your data in your app where it belongs. A few next important steps for Solr which are being worked on are - New set of APIs /v2/ that gives a more unified experience - More analyzers/tokenfilters/components configurable via APIs - Easier getting-started with basic auth and SSL, add LDAP and more - Mature the streaming/SQL stuff All in all, the competition drives both products to new hights every year! Disclaimer. I'm a Lucene/Solr committer and consult on both products