DO NOT confuse clamping-force with braking-force. Just because you can generate the same braking-force with 1-finger on V-brakes compared to 2-fingers on canties, doesn't mean that you'll stop faster. The maximum-deceleration rate will still be limited by the tyre's friction on the ground. With either set-up, you'll still be able to generate enough clamping-force to lock up the rear tyre or send the rider over the bars with the front. With either type of brakes, under maximum-braking, you'll end up with exactly the same braking-distances. Just that you'll need to squeeze the cantis a little harder that's all.