While we have been using SOLR for a while now, ElasticSearch has caught our attention lately. Built-in distributed support and the ability to nest or group documents is very interesting.

Here is a quick comparison of SOLR v.s. ElasticSearch:

http://www.findbestopensource.com/article-detail/solr-vs-elasticsearch

And an interesting thread on StackOverflow:

http://stackoverflow.com/questions/2271600/elasticsearch-sphinx-lucene-solr-xapian-which-fits-for-which-usage

Is ElasticSearch mature enough and production ready?