Sable Brushes to Contour the Composite on Surface: Is this Effective?

Dr. M. asks:
I took a course in cosmetic dentistry where the instructor used a stiff sable haired paint brush to contour the composite on the facial surfaces of the maxillary incisors. He explained that this enabled him to create a more aesthetic contour that could not be achieved with rigid metal instruments. I am just wondering about the additional cost of having these expensive sable brushes and using them once and throwing them away. How cost effective can this be? With my nitride coated instruments, I use them over and over for years. Any of you using brushes and do you feel that makes much of a difference?