Joomla is heavy CMS compared to WordPress, so Joomla require reliable hosting and contact back ups. Before you decide to build your project based on Joomla, you must know that Joomla hosting is a bit more expensive and there are few trusted Joomla Hosting providers. You need VPS or special hosting, before you jump on the first cheap un-managed VPS, be sure that you enough knowledge related to Apache settings, .htaccess and security.

Up to date system requirements are posted in Joomla Group at WebmaisterPro:

Joomla System Requirements