Our company is a small (non-technical) startup who is currently going through a developer transition, and we considered bringing in a local web development firm to work with us on a project basis.
I sat down with a developer from one of these firms, and gave him a tour of our code base. He seemed like a pretty bright guy, and while he admitted no experience with our particular PHP framework (rhymes with 'Bend'), he appeared to be a totally capable developer. We found out the next day that they didn't want to work with us because of our choice of framework.
For people who do consulting or work for development, how much does a client's choice of framework influence your decision for taking the client? Obviously, language and platform make a huge difference (I wouldn't expect a PHP shop to write C#), but as a developer I would always pick the client using any framework, over one that does not.
I know everyone has their own comfort level and areas where they specialize, but do you feel comfortable tackling a new technology armed with only some API docs and google? Do you try to make this as clear as possible to the client? What are some reasons you would turn down someone for their choice of framework (assuming it fell into your basic realm of knowledge)? And with all the frameworks out there, how is one developer ever expected to pick something others can support?