Maybe I am biased (GTK guy since 2000), but I was never really fond of wxPython.

wx aimed to be a common API for Unix/Linux and Windows, so it's basically a wrapper around GTK and the Windows MFC. If you have to write applications that run both on Windows and Linux, wx might be worth looking at (although PyGTK runs fine on Windows, too, nowadays). But when only developing for Maemo, you should consider dropping the additional layer of wrapping and directly use GTK/PyGTK.
The biggest problems with wx on Linux arose whenever a new major release of GTK was published and wx still requiring the old release due to incompatibilities.

Just my 2 Euro-Cents...