Amazing module that integrates with both the db and solr (it also supports other backends but some contrib modules don't.)
Here is a quote from Mediacurrent "Great module for search, I use this on nearly every site now. There are many companion modules like Search API Pages, Search API DB or Search API SOLR that you will need to install as well. With Search API a big advantage for me is that I can build a site using the database initially to save time and then add SOLR later if that is what the project requires." http://www.mediacurrent.com/blog/top-drupal-7-modules-winter-2014-edition
Integrates with views, facet API + facet search, autocomplete, spell check (solr only), location proximity search (solr only, using geofield and geocoder)
Soon, I hope to implement some great search functionality for this site.
Make sure to watch this DrupalCon Prague vid if you are new to this module. It will explain quite a bit and make you sound like an expert when you talk Drupal search :) https://prague2013.drupal.org/session/building-amazing-searches-search-api