index engine based on Lucene, that
refresh_intervalat 1s by default
and a lot more (ES + exposed Lucene settings)
Solr may be the weapon of choice when building standard search applications, but Elasticsearch takes it to the next level with an architecture for creating modern realtime search applications.
Percolation is an exciting and innovative feature that singlehandedly blows Solr right out of the water. Elasticsearch is scalable, speedy and a dream to integrate with. (Ryan Sonnek, socialcast)
more features not covered: