An interesting debate this one!
One other important difference i found is the Glance factor - it does take time to not be able to glance for instance at the Airspeed to see green, white arcs , and vsi etc..
Operation of the unit can easily be learnt on the grounds with mock ups.
Another difference with the DA42 is stability - it does float around more than a seneca which tends to sit more like a lump where you put it.