There are python-specific gui-api such as kivy (successor or pymt), pygui (based on pyrex), pyui and nufox, which do not compare with the more robust toolkits like wxpython, pyqt, pygtk and tkinter.
They are just extra optional tools.
The only thing unique about them is these are python-specific api, just like there are prima (perl-specific api) and shoes (ruby-specific api). It helps us to understand that when tk is tcl-based port of api (and others are c and c++ based), then these api are specifically done for the respective three scripting languages.
Out of these, kivy is the most robust, whereas pygui's coding is mentioned to be very python-like, pyui is least robust but worth trying and all of these should be portable wherever python or python-based application goes.
Then there is jpype which is a toolkit usable with jython and pydev, and which is actually java's japi customized under python/jython-interface.