Working in a fun, fast-paced web development environment such as Wide Open Technologies, primarily a PHP shop I might add, a developer could easily put their eyes on 3-4 different frameworks a week. As you get familiar with these frameworks, you quickly identify the things you like and dislike about them, but at the end of the day, if implemented the way they were intended by their creator, they all get the job done or at least have an extension to get you there.
This process has been pretty straightforward for me, as existing projects have forced me to learn whatever platform they were developed in. I quickly blamed the frameworks at first when bottlenecks identified themselves, but ultimately it came back to bad implementation. Badly optimized queries, no indexing, all issues of which point to programmers knowledge, not the framework itself. If you’re a bad programmer, all frameworks suck, so don’t spend too much time spinning your gears on which framework to learn. Just find one in the language of your choice and pick that thing apart. It will not be a waste of time, because, at the very least, you will gain experience and a core understanding of MVC.
For the next “Googler” eagerly searching for “Which Programming Framework Should I Learn”, anticipating the be–all, end–all answer, I will tell you this. Frameworks come and go, so unless you are targeting a specific job just go with the currently most popular one in your language and have fun!