Unlike most four buckle overlap boots the forward flex on the krypton is smooth, progressive, and reboundy. Laterally these are as stiff as any other top tier four buckle boot. For anyone that has ever had problems keeping their heel locked down, this boot is for you. It has all the support and rebound of the flexon with a little more weight and beef for the harder conditions. I also really like how easy it is to customize the cuff alignment, boot boards, flex, tongues, and buckles -- you can do it all with one tool. Why manufactures still rivet buckles is beyond me! Unless I end up skiing exclusively on east coast boiler-plate I dont think I'll ever go back to an overlap boot.