From using both and giving Ruby a really good try. I've concluded that CakePHP is faster, supported by more hosts, and easier to use. Ruby on Rails is clean and functional but seems best left to the purists.
I've ever tried cakephp. Cakephp is great in no doubt. but because it is laid in php 4 which is not very object oriented, it has many disadvantages. For php, for now i'm moved to Yii which is built in php 5 untill cakephp has a version build in php 5. Compared to ruby, i've ever tried also, because of ruby is very object oriented compared to cakephp, it's better than cakephp in my opinions. However, for those who used to code in php, it will be easier to developed in cakephp than in ruby
CakePHP uses PHP 5. And your post kept repeating yourself. Of course if you know PHP and not Ruby, then CakePHP is the better option. The only thing in Ruby I've fiddled with is Metasploit
If you already know PHP then you should look at http://codeigniter.com/ - you can pick it up pretty easy.