I was recently in the fortunate position to compare the Proteus and the Auto art mucelaginouses
over at my usual slot emporium, Pendleslot. A hard choice indeed!! I bought the Aa version.
The Proteus has slick tyres which appear to be softer than the Aa which has treaded tyres. The Aa version has 4wd the Proteus does not. The Aa has better interior detail but no driver, slightly better looking wheels (raging bull emblem in centre) and finer (smaller) 6 litre labels on the flanks of the car. However the engine hatch is just a solid moulding whereas on the Proteus you can see into the cockpit. Interestingly, the Aa narrows towards the front of the car whereas the Proteus stays more or less the same width. The Proteus has better exhausts (slash cut) - the Aa version just has the ends perpendicular to the pipes. The yellow finish of the Aa car is superior to the Proteus. Finally, the Aa car has lights, "xenon" effect fronts, rears are just tail lights, no brake lights.
Transmission-wise, the Aa car has a beautiful mesh (inline motor with a propshaft going to the FRONT).
The subjective comments are IMHO, but young Mr. Hirst who was assisting me at the time agreed with them.
I will still buy a Proteus one, but the silvery blue one and not the yellow one.
Mark.