So you want to set-up a new website and have chosen to use a content Management System (CMS). The question is "Which CMS do I use?" Good question and to be honest, one that is not easy to answer. Essentially it depends on what you want from the CMS, both short and long term.
For example, if you are setting up a blog and have no plans to develop it further, then WordPress is one of the best choices. It is light weight, easy to use and fast. If however you want more than a blog, either now or in the future, then Drupal may be a better choice. WordPress can be adapted for these additional needs; Drupal was designed from the outset to be more than just a Blog. Now what if you want a system for education? Again, Drupal or WordPress would make are fine choices, but what about a Virtual Learning Environment (VLE) such as Moodle?
You can see it is not straight forward. There are sites that compare the functions and features, such as CMS Matrix. DevZen though, would thoroughly recommend actually test driving each of the systems you think are likely candidates and seeing if they do what you want rather than relying on the feature list.