I switched to 4000's after a bad run with Michelin Kryilions. Now those things were puncture prone. I've been pretty happy with the 4000's. Just got my first flat with the 4000 this week after about a thousand miles. ~1/2" screw through the center of the rear tire. Wouldn't have mattered what tire was back there. I was actually impressed with how the tire held up. Entire screw was embedded in the tire, head left an imprint in the tire. But the hole on the outside sealed up pretty well on it's own and only the slightest pin hole on the inside of the tire.