I wrote a framework and I am still using it, because it's more flexible and easier for me to extend than the other ones. That said, I think it was a waste of time from a business perspective. When you want to build a project, take something open source, rock-solid with a community behind it. You can focus on building your project and not fixing bugs in the underlying layer.

Before writing my framework, I had written another one and learned a lot. The second time around, I've made something really powerful and cool, and it really helps me. But it's still not as thoroughly unit-tested and consistent as the ones built by a community. I'm just one guy.

By the way, in cae you want to see it: http://code.google.com/p/pal-framework/ :) It's open source.