johngchristwrote a review of Avid Juicy/BB7 Disc Brake Pads on August 4, 2015
Familiarity: I've used it several times
Organic/semi-metallic/resin pads are softer and tend to be quieter. They offer more initial bite, but fade faster than metallic pads on longer descents. Do not use organic/semi-metallic/resin pads in wet conditions.
Metallic/sintered pads last longer, handle heat better, and resist fade better under heavier braking loads, making them good for downhill. In wet conditions, metallic pads are a must.