Mike Davies has posted a comparison he's worked up between the CakePHP and Symfony PHP frameworks:
Asking around in work (well, the extended group of web developers that used to be the phenomenal Yahoo Web Dev team in London, and Munich) for PHP framework suggestions, the most frequently recommended one was Django (go figure!), followed by symfony, Code Igniter, and one solitary suggestion of Cake PHP.
He gives overviews of each citing things like features, database integration, how they implement MVC and documentation. His comparison is quick, pointing out that the right tool for his job ended up being symfony - a bit more complicated, but more of what he needed.