Actually I forgot one major difference. There is no run up required.
You simply hold the TEST buttons in and it runs through an automated check routine which switches FADECs, cycles the prop etc....This is quite useful if you have a longish taxi, on the taxiway, simply hold the TEST button in until the checks have completed (15 seconds?), manually swap FADECs (Switch to B) to check that works, switch back and that is it, you are good to go (after doing pre-take off checks of course).