Is it the vehicle's ability to accelerate from 0-60 mph? Corner at 1.0g? Brake from 60-0 mph? Obviously, while acceleration is exciting and cornering is fun most of the time the ability to stop is even more important! Performance isn't just about speed. It's about controlling speed.
Today there are premium brake pads and economy brake pads. Premium brake pads are for drivers who know the value of quality, high performance brakes. Economy brake pads are for drivers who shop based on price and not performance. Before you buy, "stop" and think.