A while ago now, Fabien Potencier and Francois Zaninotto were interviewed for the Zend Developer Zone blog and Fabien commented on how symfony is really better suited to larger web applications. I am here to counter that statement and show that symfony is good for all your web projects.
I can understand why Fabien would make a comment like that. To get going with symfony can be a little bit time consuming and to get to grips with its architecture and how to "code for symfony" can again take some time. But if you have already used symfony and learnt how to use it or plan to use it for all your projects, then those disadvantages fall away.
There is another reason why I feel symfony is great for even the small projects. How many "small" projects actually stay small? How many times have you started work on a project that is supposed to take only a few weeks at most to finish and it ends up still in active development months later? The problem with starting any project with the mind set that its only a small one is when it suddenly grows to be a rather large application, extensability and maintenance starts to become, well, a little nightmarish.
If you start a new project, even a so-called small one, with symfony, the abstraction required for good extensibility and maintainability is enforced on you. If this project suddenly grows its not a problem because everything is already setup to allow it be expanded.
An example is here at Synaq, one of our Senior Linux Technicians, a guy who usually works on setting up new servers, was asked to create a simple little interface for a Small Business Firewall product we are developing. This application was only really supposed to pull basic info into a simple interface for a customer to read. The problem is that now, more functionality than was originally planned needs to be integrated into this little app and it now needs a database backend to accomplish that. If the project had been started with symfony, it would have been a simple case of creating the database itself, sending a couple of symfony commands to generate an ORM model to interact with that database and 90% of the work would have been done.
After chatting with Jason, the System admin developing this application that used to be considered small, and explaining symfony, he is thinking of migrating the application to it. Ajax was another example. Some of the functionality that was added to the requirements of this little application was that data be updated on a few pages every few seconds. This meant that Jason now had to learn the Protoype library. With symfony he could have just used the built in helper functions to accomplish the same thing.
The biggest problems with "small" projects is what people don't forsee. A lot of the time these projects end up growing in requirements and suddenly turn into large, unwieldy projects that are difficult to maintain and extend with new functionality. By using symfony you may have a little slow down (perhaps) in the beggining, but you will end up with a far more robust and useful framework around which you can almost infinitely extend into the near future.