Wordpress is a good platform. Lots of themes and plugins and incredibly popular.
My only problems with Wordpress, aren't really problems with the platform, but with the people that use it.
1) Huge security risks if not properly updated and managed. There are always security updates coming out. Some will apply the new updates, many will not. With millions of Wordpress sites out there, hackers know that if they can hack one Wordpress site, they have potentially hacked millions of sites at the same time as they can apply the same exploit to the other sites running the same version.
2) The so called "developers" that charge customers a premium for a website, and they simply install Wordpress and a few plugins. I can't tellyou how many custom web development jobs we have done for customers who's original developer convinced them they should use Wordpress, then found out that was not the best way to go!