Great Curve

Many believe that when throwing a curveball you should twist the wrist…this is a false statement. When throwing a curveball the best way to do it is to basically snap your fingers while throwing the ball. This gives the ball(in my opinion) more curve, and is easier on the arm.

Has anyone been told different or disagree?

One of the important things is how you pull the ball from your glove.
When the arm is extended behind you, the palm of your hand should be facing toward you (or towards the plate).
To throw the curveball,
use a slashing movement of the arm (some people have likened this to a karate-chop).
It produces great movement, and is less harmful to the arm than other ways of getting movement on the curve.
Throwing differents pitches consists of wrist and forearm angles.