Just a quick plug. I’m building my first project with PyroCMS. I was already a fan of Codeigniter, the core behind PyroCMS, but so far I’m impressed with just how easy it is to set up and extend CI with PryoCMS if you’re already familiar with CI and MVC. It lacks the community that WP has supporting it, so you’ll need to be prepared to do some custom code. But in a lot of cases it’s the ability to customize that you really need, but you don’t want to have to build a backend from scratch. PyroCMS seems to serve this purpose very effectively.