We’ve been using WordPress since before it was named (seriously) for our own sites and our client sites as well. In fact, this site is driven behind the scenes by WordPress. The next release of WordPress has been in the works for about a year and includes some pretty serious changes that we are just thrilled about.
Perhaps what has the most potential for disruption in the small-footprint CMS arena are the Custom Post Types, which are going to allow almost any kind of content to be managed in administration forms that match the way people think about what they publish. We are currently in development with a client who is needing custom Event Pages, so we’ll probably work with Custom Post Types to make that happen for them.