Hi ElasticSearch team,
I am a user of both Solr and ElasticSearch. ElasticSearch has lots of advantage over Solr, but it has big shortage compared with Solr: ElasticSearch's reference documentation is not good as Solr's. For example, there is no exhaustive description about ElasticSearch's configuration file elasticsearch.yml in one central place rather scattered all over the reference documentation; thent lacks completeness. After I go through the whole reference documentation, I can't get the complete picture about the query and aggregation syntax. If you like to get more concrete what I'm talking about, you could refer to Solr's link https://cwiki.apache.org/confluence/display/solr/Searching. Solr does much better than ElasticSearch on these things.
ElasticSearch is a great product, I look forward to it becoming better.