This should probably go to the top. If you have a small application (say less than 10.000 lines of code) the framework probably isn't your problem anyways. And if you have more code than that, it's still not that hard to switch systems when you really have to. In fact even switching out core components like an ORM is possible and achievable if you write a little shim and get rid of that step by step. Better spend your time making the system better. The framework choice used to be a lot harder when the systems were incompatible. But this clearly no longer is the case."

http://lucumr.pocoo.org/2010/12/24/common-mistakes-as-web-de...