I've been using 700c x 36mm SMP for 5 years now, 2 metal flats. 6 or 7 tires with a total 41,000 tire miles. None retired yet, one had a 1/4" tread cut. My tour bike was 120 + 170 lbs. ZERO worry.
Yah they feel stiff sometimes, but they don't care if 55 or 75 lbs air. My air gauge broke in Vietnam where replacements don't exist. They will go half around the world no doubt. My 3 year old tires are still good enough for a trans-am this spring I think. Only tires I use now.

I am finished with any Conti tire again, damn crackers.