will drop and fluff if smooth round implants are used. If textured anatomic implants are used, you are not supposed to drop and fluff. Over the muscle implants have more tendency towards the rock in the sock look down the road. The only nice thing about going over the muscle is that there is no distortion with muscle contraction.
If you have a moderate amount of breast tissue silicone implants work very well. They will not drop anymore than normal breast tissue.