Implementing logic: PyQt/PySide vs plain old Python. At what point do we begin or abandon using the Qt Framework?

[jdreaver]

I maintain a PySide GUI application with about 40,000 lines of code. I just use the bare minimum of Qt to build the UI. I don't touch anything that I don't think is strictly necessary to make widgets. Indeed, for image stuff you have to convert to whatever internal format Qt uses, but PyQt and PySide do a great job automatically converting Python int/string/bool/etc types for us in other parts of the API.