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Search engines - search appliances
solr appliance price
google appliance price
However I think for people just starting out with Lucene based indexing ElasticSearch seems like the better starting point, since its much easier to setup. That being said in terms of features it has pull past Solr pretty quickly too, so I think its only a matter of time until we start using ElasticSearch and maybe even drop Solr entirely. They seem to have serious issues maintaining their original speed after merging your subversion repo with Lucene.
Exalead
French company making its offering available in the US market.
The product does everything. Full text search, faceted results (categories with counts), sorting and filtering on arbitrary fields, adjustable field weights. Supports function queries too, just like Lucene.
A comparison of search solutions - Solr-Lucene/Google Search Appliance/Exalead
Semaphore adds semantic capabilities to GSA to improve search results and usability. Semaphore is enterprise semantic software that delivers an exceptional user experience for portals using the Google Search Appliance.
also fast search and solr and sharepoint
Microsoft recently introduced a new global initiative, Business-Critical SharePoint Program (BCSP), focused on helping companies use SharePoint to capture maximum value from their Line-of-Business data.
Enterprise search technology is incredibly useful and powerful, but very few people understand how to apply it well. Perhaps because search looks so simple on the outside, or perhaps because of the universal familiarity with web search
http://www.bainsight.com/sharepoint-fast-search-connectors/Pages/default.aspx
Connect All Your Critical Enterprise Systems into SharePoint for Unified Search and Information Access