> It's just a random guy with a more expensive car.
The big one is they are required to be commercially registered and commercially insured. At least here in Chicago it's usually the private chauffeur's with a livery license plate in sedan/limo. I'm guessing they do Uber black on the side.
Anyway, yes they are "just random guys" just like any other Uber driver but they've had to jump through extra hoops which affects who does it. I'm not saying that causes a better selection but there is specific difference between the two, other than just requiring a better car.