The fact that armed citizens stop some 700,000+ crimes annually, while the number of shots fired is about 1/20th that amount, tells me that "brandishing" is not only occurring roughly 95% of the time, but that it's a highly effect deterrent, as well.
That's not a plug for brandishing in general, as displaying a firearm is against the laws of all states. Then again, so is using a firearm. The key are the exceptions, such as "except when faced with imminent threat to life or limb."
Personally, if I cannot simply leave the situation, I'll leave my firearm holstered until drawing it becomes absolutely necessary. That doesn't mean I will automatically fire. It does mean I will draw it only if absolutely necessary. At that point, the ball game goes into overtime. Will the perp back down? Will he continue, or worse, accelerate? If the latter two, then firing becomes the only remaining solution.