I've been using cakephp for many years now, it's very fast to develop applications with so much flexibility (MVC). It has some great tools like form helpers, validation etc which makes development easy. Also, if you're looking out for speed then this is your best bet as well. There aren't any downsides that i can think of. We use cakephp in our project for several clients' websites. This framework provides us an integrated solution where we are able to easily manage all client-specific data from one place, without having to update multiple databases or webservers.