I wanted to give Continental tires a go thru REI because of a gift coupon and their 20% discount tomorrow. Some of the reviews for the 4000 have been good, some bad, in regards to flats. I currently ride Armadillo Elites and have ridden hundreds of miles with zero flats. My question is are the 4000 more "durable" than the 4000s (no REI reviews for the "s" version) and how will they be compared to the Armadillo. I am a non racer, 165lbs, and my usual rides are 50+ miles. Thanks for any specific input.