I have been using them on my trek road bike for years. I average less than one flat per year (I ride 5,000+ each year). Expensive tires but they last. My 32 mm tires will last over 5000 miles.
I've ridden on Conti's for several years. My last set was a 25mm GP5000. This time I went wider to 28mm. The tire really sticks to the road. If you air down a little with the wider tire the ride quality is great. My rims are 19mm internal and when mounted the tires measure right at 28mm or just a tiny bit over. I weigh around 155 and ride with 70 psi front and 75 psi rear. My only complaint is I've had 2 punctures in 1100 miles. I guess you can always complain about the hassle of punctures that can happen with any tire under all sorts of circumstances...however, I was hoping for a little more resistance to the common thorn or glass. I recommend them for all around riding. The weight is also good for the size and all around type use.
I run 27 front, 28 rear on Enve 4.5AR wheels. mounting was a breeze and they inflated super easy. I follow Enve's recommended PSI in general but go a couple PSI above recommended (59 front/60 rear). The 27's inflated and settled in at 29.5mm which is just at the 105% rule on the Enve 4.5Ar's. Riding in CO on mountainous chip N seal and these tires are supremely supple, smooth and handle wonderfully. They are very fast too. I run a Power meter and can verify they are faster on real roads and climbs than what a steel drum indicates. :). Even at higher PSI's for my 167lbs on 25mm internals, they run more supple and smooth than Schwalble Pro One TLE Addix's by far! I do wonder by some of the reviews if an earlier production tires had issues ? The rubber is a little softer which adds to the road feel and cornering stability but Im not concerned about getting the longest lasting tire, I am happy with the best rolling and handling tires. I ride about 2K miles a season and these are my favorite tires I've ever run.