My general rule of thumb is that the usefulness of frameworks is inversely proportional to the complexity of the application you're building. If you're making a pretty generic data entry and reporting app for a small base of users, a framework will probably be a great boon to you. If you're building something that will require a lot of unusual web app behaviors, or need to scale very large, you will probably find yourself cursing any large framework you chose and looking for ways around it.