Disclaimer: I don't want to start any flame war so there will not be no name of any framework mentioned.
I've been using quite many from the existing PHP frameworks and my experience in each case was similar: everything is nice a the beginning but in the moment you require something non standard you get into lot of problems to fix otherwise simple issues. In case of frameworks following the MVC design pattern there are some issues with the implementation of each layer for example there is a lot of codding used for model and data access with using ORM and presentation is not much more than pure phtml. Some frameworks use their own wrappers for existing PHP functionality and in some cases severely limiting original functionality. Depending on framework you can have additional problems like lack of documentation, slow or non existent development cycle and last but not least speed.
While ago I made my own framework which while doing it's job and being used for few different applications after couple of years more of experience with PHP doesn't seem to be perfect piece of codding. I could write my own framework and use additional experience I've gathered during these years to make it better on the other hand I'm aware that there is quite many better programmers working on creating/upgrading existing frameworks.
So does it make at all nay sense to write my own PHP framework if there is so many possibilities to choose from?