I have these tires (I think 23mm) on my Lemond Titanium bike. Sunday, I rode the Tour de Bronx 45 miles and then I rode another 15 miles in the city on fairly rough street surfaces. I experienced no harsh ride or fatigue except that my shoulders ached near my spine at the end of the day. I've made some progress with lifting weights and doing pushups, and I believe it would have been worse without those workouts, so I can't blame my pain on the tires. I weigh about 155 now, and I inflated the tires to 90 psi front and rear.

They were hard to install, and while I expect them to stretch, I don't know how much or when. I didn't want to take a chance in case I got a flat on my ride, so I brought along a Kool Stop Tire Jack. It stuck out of the end of my toolbag, but it's lightweight. It makes mounting tight tires easy and safe. I recommend this tool highly.