Even if very simple, from this tutorial should result clear to the reader that both the MVC and Observer patterns can strongly improve the quality of middle and big size GUI applications, especially if combined with the use of glade-based views.
pygtkmvc has been extensively used to produce a few large GUI applications based on Python and Pygtk-2. In this scenario, many design choices that led to pygtkmvc had been determined from practical needs, and this made easiness and transparency the most appreciated quality of the framework.