I had a chance to benchmark two major searching engines, ElasticSearch and Apache Solr.
My first impression was that ES was easy to understand and build an environment while Solr was flexible enough to suit to any use cases.
Regarding performance, it depends on the use case of course, in my case, ES was faster in general search such as keywords AND/OR query. In faceting, both engine showed similar performance. Since query syntax is completely different between them, learning cost(eg.time) is considerable..