My company is a custom software services company for external clientes, which means our typical project is one in which the contract already states the full budget of the project.

Our typical project starts by defining requirements (improving the proposal high-level requirements), then we code the project, test it and ship it. We have an acceptance phase were the client tests the software and in that phase we can usually implement small changes asked by the client, or we charge extra for change requests.

In some projects we have intermediate releases so the clients can check the progress of the project and give feedback on it.

In summary: something like waterfall...

I've followed the "agile" movement for a bit now and I always see it being a good match for a "product" company, or a company building software for an internal client. But are there good stories / advantages on using agile methods in my kind of company/projects?

What are your experiences, what do you think about this?