Hostgator in their blog post have announced that they have developed an in house script for oneclick installation of web software scripts. Because it is in-house faster updates are available. it is simular to Fantastico de luxe one-click installer. According to their post they offer free installation anyone having dedicated server or vps at Hostgator. Scripts included for fast installation are: blogs: wordpress, lifetype, b2evolution,, nucleus, content management systems: joomla, drupal, shopping carts: opencart, zencart, oscommerce and lots of other PHP scripts. Because it is still in beta stage youu may encounter bugs, for which you can submit ticket to hostgator support. As for user reviews, there are couple in host gator forum, showing good response.
http://forums.hostgator.com/quick-install-beta-f41.html
http://blog.hostgator.com/2010/07/30/july-2010-newsletter/