For some of our systems, we use Alfresco and/or Drupal, both which have Apache Solr as an easily-configurable search backend, and which works basically plug-and

For some of our systems, we use Alfresco and/or Drupal, both which have Apache Solr as an easily-configurable search backend, and which works basically plug-and-play with the respective systems' content permissions. Using the free versions of all three (Solr + Drupal + Alfresco), search is fast and access-controlled very easily. I worked for a company that had a Google Search Appliance about 6 years ago, and, like others have said, it basically sat in a rack somewhere and collected dust once we started using some form of integrated search. The GSA was fast and relatively easy to use, but required an expensive initial purchase + ongoing licensing/update fees.