I have never heard of Qcodo.
CakePHP is a full featured framework with a lot of automagic, but unfortunately it is one of the slowest frameworks out there. It also doesn't have official forums, and there really isn't that busy of a community. It tries to be a Ruby on Rails clone, but that just doesn't work so well with PHP.
Zend is impressive. It has a strong community and a corporate backing. It is very featured, but it is also very bloated (see that benchmark) so it has moderate performance. From what I hear though, you are able to use the components separately without using the whole framework, and can even use them with other frameworks!
I use CodeIgniter at work and I love it. It is by far the most newbie friendly framework, and with your CakePHP experience it should be a breeze. It has very good documentation that is thorough, clear, and well written. There are a few features that it doesn't have (such as an ORM) that other frameworks have, but CI has one of the most active framework communities I've seen. Since it's easy to write libraries for it, you can find a library to do pretty much anything you want to - ORMs, authentication, etc. To add to this, if you want an ORM for CI, I recommend DataMapper.
You may also want to check out Kohana. It's a spin off of CodeIgniter. It's strictly PHP5 and has an ORM and some more features. Haven't used it myself though, but I have heard good things.