But Minn, knowing how a servo works and the difference between digital and non-digital is important to picking servos. Otherwise, you might be surprised when a 45in/oz digial servo allows you to hold a better knife edge than a 60in/oz standard servo. Unless you understand the drop off in torque with standard servos, you could end up with servos that just aren't up to the job for acrobatics. (making the example up, btw. Don't quote me as saying a 45in/oz digital is equal to a 60in/oz conventional in holding ability).

Btw, in some 3D such as hovering, you don't tend to hold the controls hard over against the airstream much. So holding power isn't as critical. Servo speed matters more in a hover so you can make the very fast corrections needed. On the other hand, a knife edge loop is going to require much more holding power, but the servo speed matters a lot less.