Apparently you’re not that experienced. The three big ones I’m familiar with are Cake, CodeIgniter, and Zend. All of which are different. It depends almost entirely on what your preferences on working with frameworks are. Cake is a very easy framework to learn however some people dislike it, because much like Ruby on Rails, does a lot of things automagically. Respectively, the other two are progressively more difficult, and do less "for you". Some people like it, some don’t. Just play with the frameworks and see what you like best. You’re probably not gonna fall in love with the first framework you try.
