Getting started with Qt is pretty easy I'd say, at least when you use Python and not C++:

   import sys
   from PyQt4 import QtGui

   def window():
      app = QtGui.QApplication(sys.argv)
      w = QtGui.QWidget()
      b = QtGui.QLabel(w)
      b.setText("Hello World!")
      w.setGeometry(100,100,200,50)
      b.move(50,20)
      w.setWindowTitle(“PyQt”)
      w.show()
      sys.exit(app.exec_())
       
   if __name__ == '__main__':
      window()

In general I think Qt is one of the best-documented UI toolkits out there, and while it surely is complex it offers a lot of modern features and is able to produce pretty great UIs.