First up are you talking html framework - like twitter bootstrap or a programming language? If it's server framework and you are happy to use PHP then there are quite a few and the proponents of them can be very vocal about their choice. Check out some of the other threads. FWIW I use cakePHP, not the most popular but it's easy to work with and I get sites up and running quickly.
Did you take a look at cakephp? Did you search for the other threads? If so, what did you think of the frameworks they discussed?
Isn't it bit hard to learn? I would like to go with codeigniter. Because documentation is solid and very easy to learn if you know object oriented programming. And user base is much larger than cakephp.
Well, I think both is good. OOP and procedural are different approaches for same problem. But some frameworks ties hard on OOP. Because it is good design method. Even cakephp and codeigniter use OOP as a convention. Since PHP is not a originally OOP language, it has freedom unlike Java or C#.