I also think WP is the fastest, easiest way to set up a CMS quickly. Plus, there are a ton of plugins that allow you to modify for SEO. I also used a program that allows you to set up a paid membership and drip the content to the new member if you are setting up a paid membership site.

What I like most about WP is the fact that there are so many developers out there contributing new and cool plugins for it, almost on a daily basis.

One last thing I want to mention is the fact that if you set up WP correctly Google loves the linking structure and you can get ranked pretty fast for your long tail keywords. Just remember to change how WP names the pages so you don't end up with a ..../?P=12 Page but a ../long_tail_keyword