Drupal is an open source CMS that has almost all the features of commercial CMS packed into it with customizations that are readily available from the community of users. You just have to tweak in the right add-ons with the help of a Drupal Expert. Once this is done the maintenance is much simple that most other CMSs. Main advantages of the Drupal are:
1. More than 7,000 modules that are on offer.
2. Active user community ready to help you in development and design oriented changes.
3. Many marketing and campaign friendly components and add-ons will make overall website maintenance very simple.