I'm currently riding a S-WORKS M5...I love this bike, Specialized really pays a lot of attention on the way they build frames...the tube thickness changes in differant areas, its wider near botton bracket for additional stiffness, then the shaping changes near the head tube for more vertical stiffness, even the chains stays on the drive train side is a single piece, with the weld on the opposite side. this bike is a climbing machine, mine weighs 22lbs fully built, sure I could make it lighter but 22lbs is plenty light enough....you cant go wrong with an S-WORKS frame...