Wordpress started off as a blogging platform a long time ago and now powers over a quarter of the Internet.
How did it get here? Well, there are actually two ways you can use Wordpress:
Recently Wordpress.com has decided to allow any custom plugin and theme to be installed on the $25/month plan. This is huge, because if there's one thing that sets Wordpress apart from all the other website builders it's the ocean of plugins and themes it taps into. Basically, almost anything a website can do, there's a plugin for that. Most niches and needs are covered, and lots of the plugins and themes are also free.
One area where Wordpress stands behind the competition is the usability. This is somewhat to be expected given the sheer power Wordpress has, it's very tough to hide away all that complexity. Plus, all those custom themes and plugins each have their particular way of doing things, which can get very messy when you have dozens of plugins installed.
Another reason Wordpress is a bit cumbersome to use is it's not a drag and drop editor, but content is entered in forms. This separates the design from the content and makes everything less enjoyable. If you have previous experience with the Wordpress admin area you'll be ok, otherwise prepare for a bit of head scratching at first.
There's a free version available if you want to test the waters. Paid plans start at $4/month