At the beginning, there was only the pitch / roll rate settings.
It was introduced because the looping and flips were way to slow with default settings.
The principle is to decrease to correction control when the sick is far from the center.
This way, the rotation rate is less constrained when the sticks are not centered => with a value of 1, you will have the maximum possible rotation rate and the ability to do multiple flips per seconds.
It acts as a "super expo", and you it doesn't change the accuracy near the center.
The RC RATE was introduced after specially for Warthox
The purpose is just to be able increase the rotation rate in a linearly way.
So it depends on what you expect.
- want to fly cool and be able to do fast flips sometimes => pitch/roll rate
- want a very nervous multi in all circumstances => rc rate
Now you have the choice, and you have also the rc expo curve acting as a third parameter.
