I have >13,000 km on Hutchinson Atoms (23mm) with no sealant. They are on Campy Eurus and Shamal 2-way. Two flats from punctures and one flat from user error when the valve stem came loose on the rim when pumping up and I did not notice. I have never had trouble mounting them or changing to a tube on the road. The Atom Galactic (243g actual weight) is lighter than any clincher tire and tube and can be ridden every day. Why would I use anything else?