At KnackForge we thrive hard to deliver best Drupal sites. As a part of this cause, for our potential Drupal sites we opt to use Apache solr as engine offering searching functionality. This makes our sites more scalable.
Recently team KnackForge was engaged in developing a massive Science News publishing site inspired by eScienceNews.com. More details about this site can be found in this case study page in drupal.org.