I manage a wordpress installation for a school community site - wordpress's greatest strength (and biggest source of frustration) is it's flexible and popular plugin ecosystem that gives me useful plugins, including a shopping cart system for fundraising, an events calendar and photo galleries, all managed from the same WYSIWYG interface as a blogging engine and a decent CMS.
I could re-write all those plugins in another CMS, but the fact that wordpress is so popular and so flexible is the reason I don't see myself replacing it any time soon.