Battle of the Giants: Apache Solr 4.0 vs. ElasticSearch 0.20 by Rafał Kuć.
A very nice summary (slides) of Rafał’s comparison of the latest releases of Solr and ElasticSearch.
They differ and those differences fit some use cases better than others.
And the winner is: … (well, I won’t spoil the surprise.)
Read the slides.
Unless you are Rafał, you will learn something you didn’t know before.