Symfony is far more complex than CakePHP. This can be read as a defect of Symfony (from the ones who are looking for semplicity) or a major flaw of CakePHP (from the ones who are asking a lot to the framework).
I love CakePHP: it licterally saved my life.
CakePHP lacks a lot of important features, which ae not immediately visible to every developer.
No doubts Sympfony is much more hard to learn and use. No doubts CakePHP has a set of serious flaws that may limit it’s use.

CakePHP: genial, simple, quite light, easy to learn. Can be limited, too much simple
Symphony: much more hard to learn, a bit slower. But it’s the state of the art of frameworks. When you start thinking Cake lacks something, take a look to Symfony, it may have what you’re looking for.

Symfony has Environments, custom sets of settings to manage test, developing and production setting. Cake has nothing like that: just a simple, poor set of configuration and bootstrap files. Symfony has a very advanced system of cascading configuration that allows every kind of granularity. It’s like having configuration with inheritance. Can it be useful? You judge.

Cake’s ORM is really simple to learn and use and it fits most of the requirements. Most of applications don’t need anything better than Cake’s ORM. But it’s very limited too. Cake’s ORM is the biggest Cake’s limitation (that’s why CakePHP team is working on a new ORM engine for the next Cake’s realeses, take a look to the road map). Cake’s ORM manages arrays while Sympfony’s one (Propel or Doctrine) offers a serious and professional ORM. “Lazy loading” is unavailable on Cake and developers must make use of workarounds like $Model->recursive, Bind/UnbindModel and the Containable behavior. Symfony’s ORM, on the other hand, retrieves real objects, which expose real methods, with lazy loading. Workarounds like the callback methods BeforeFilter, BeforeSave and so on are just, ehm… workarounds. If only Models in CakePHP were real objects able to retrieve objects and not arrays, they would be completely useless. Doctrine and Proper allows Symfony’s developer to completely separate Business Logic to database. On Cake a Model cannot be a real business logic object, because it’s linked to a table, it executes queries and so on. This is simpler and can be very useful until you have to develop a very very advanced application. Then, Cake’s ORM flaws emerge. And then you will appreciate Symfony.

My opinion is: learn and use CakePHP first. It’s a magic framework and working with it is really joy. There’s nothing better than CakePHP, until it stops fitting your requirements: no CodeIgniter can equal the Cake’s facilities. When you start being annoyed with Cake’s limitations, take a look to Symfony: you will be already prepared to concepts like conventions over configuration, standard directories structure, MVC, ORM and so on, and you will be able to appreciate the hardest parts of Symfony: they are there to overcome Cake’s flaws.

By the way, I’ve found a broken link, at the foot note on the previous post. It’s pointing to a 404 page, but it should point here, I think.

However, after reading this article and several comments, I am going to try CakePHP with the hope that it will be easier for me to learn.

Comments on symfony are also welcome on Twitter.

Zend is good too, and is coming along nicely (check out 1.5 PR). I use both Zend and Cake, and with Zend you get more flexibility over everything, including the directory structure. But of course that flexibility comes with its own responsibilities and details that cake just manages for you. Sometimes that’s good (new app) sometimes its a liability (upgrading exisiting app).

It can be used as independent libraries (which is a nice feature), but when you start using the frontController, MVC, and other core libraries the difference between it and cake start to really fade. 1 important distinction to make about Zend is this: Its not a Rapid Application Development framework. RoR, Cake – those are RAD frameworks. But that doesn’t make Zend ‘not’ a framework. Its just a different kind of tool.

Oh and one last thought… Cake’s support of PHP4 is a feature, not a bug. And is one of the few frameworks to support it. I use 5 when and where I can, but sometimes things just take longer to upgrade, especially in an Enterprise environment… Hell, even Media Temple just got PHP5 for their Dedicated server plans.