Best GUI for small-scale accounting app?

[Bulba!]

I'll soon start development of a specialized small app and need 
to choose GUI for it. 

I have narrowed the choice to wxPython/PythonCard and QT/PyQT 
(buying commercial licenses is not a big problem, the company 
would pay for it).

Which is better for this kind of application? I mean, looking
from purely technological and long-term development aspects
and ignoring licensing issues:

- QT seems to be industrial-strength, but.. it's probably
more complex/difficult to use.

- wxPython/PythonCard is probably simple to use, but.. 
are there not some pitfalls that development will fall 
into once the app starts growing (they all do)?

The long lists of invoices, subcontractors and tasks (possibly
hundreds or thousands) will have to be displayed - which toolkit 
is better for that in your experience?

I would appreciate anybody sharing their experiences with 
relevant toolkits in development of this type of software
or similar.




--
It's a man's life in a Python Programming Association.