More pistons in a caliper doesn't nessacerily mean it's better. 4 is adaquate enuogh, but 6 or 8 is just rediculous. Generally (like with engines when comparing 8, 10 and 12 cylinder motors) the more you have, the smaller they need to be to even fit in the caliper, so the 4 pot Brembos that Porsche uses is about all the braking force anyone would need in a street car.