python GUI - which to use ?

[Larz60+]

Easy to use is relative as all graphics packages are quite complex. However the easiest (and by same criteria most restrictive) package is the built-in (most installations) tkinter.
Stepping up, Qt (latest version Qt5) is probably the most robust, but has limitations on commercial applications.

Personally I prefer the Phoenix version of wxpython which contains a rich library of widgets, an excellent demo package and can be used in commercial applications without restrictions. You can preview some of the available widgets here: https://wxpython.org/Phoenix/docs/html/gallery.html

For most platforms, you can install (from command line) using 'pip install wxpython'
Be sure to download the demo see: https://uwpce-pythoncert.github.io/Py300..._demo.html