[MrFlippant]

Any controller that wants to be in that class has the BARE MINIMUM requirement of adjustable sensitivity and braking. There are other things that can be added, but those are the basics.

If you want true premium/high end, you need to also include:

"Choke" - the ability to tune how quickly the power is applied, so that really fast cars don't just spin the wheels, but do eventually get up to top speed.
Power limiting - so that the top speed the controller will provide to the car can be limited. Great for making fast cars easier to drive for all skill levels of racers.

I'm sure there are others.