I've noticed faster speed, (yep, maybe 2 to 3 mph) on new, smooth pavement also. I also use 28mm tires because that is all that will fit on my bike. My original motivation for 28mm tires was to soften the ride due to a bad back. I weigh 165 pounds currently and pump up tires to 65-70 F and 85 R psi. This has been fine pressure for 7000 miles over smooth or older and rough back roads. An extra bonus has been, as Barrett has said, a versatile tire on varied surfaces. I don't worry about a bit of sand or gravel on the road.