Unwilling to rest on their laurels, Shimano addressed every aspect of their Dura-Ace shifters to ensure that they produced a peerless product. Starting at the hoods, the Dura-Ace 9001 shifter uses a new dual density hood design that improves both grip and comfort for improved performance during both aggressive climbing and cruising on the flats. The hood shape has changed as well and now closely mimics the Di2 hood shape and now provides a better match to the natural contours of the hand than 7900 mechanical did.
The lever shape has changed slightly as well with the lever canted further outboard for easier access in the hoods. The lever now angles further back as well to better match the profile of compact handlebars making the levers easier to reach from the drops.
Shimano reengineered the internals of its shifters to use more cable per shift in order to improve cable life as well as creating a more positive lever feel. Yet, this increase in cable pull hasn't ruined Shimano's trademark STI light action. In fact, shifting effort has been reduced 47% and is evened out across the cassette for a more consistent feel. When it does finally come time to change those cables, it will be far easier with Dura-Ace 9001's improved cable routing.
All of this adds up to the best shifter Shimano has ever produced, and it goes to 11!