I would be certainly interested in hearing about your experiences with Code Igniter. I'm in the process of developing my own PHP web framework for over a year now, so I am always interested to see how others do things. I just had a quick scan through the user guide on the Code Igniter website, which is pretty clear and concise, and I like the way they handle URLs in particular but I think they could make greater use of scaffolding.
Have you found that using an MVC framework such as Code Igniter has reduced the development time of your project significantly?