The advantages of an electronic shifting groupset have been well established in recent years: consistent, foolproof shifting, reliability, low weight, minimal maintenance, reduced shifting effort, and of course, the ability to shift gears even under full power. The Shimano Ultegra 6870 Di2 Groupset with Power Kit takes all of these advantages first presented by the company's top notch Dura Ace 9070 Di2 group and brings them to a friendlier price point, incurring no notable performance sacrifices and only a little bit of weight gain in the process. The magic here begins with the Ultegra Di2 shiftersbrake levers, which, like the Dura Ace Di2 levers, are fully programmable, allowing you to program actuations like how many gears upshift or downshift per push of the lever, which lever actuates which derailleur, and in which direction, and more. Those levers boss around a very obedient drivetrain, as well. The Ultegra Di2 front and rear derailleurs utilize nearly identical servos, motors, and other hardware they're Malaysian made, as opposed to being produced in house by Shimano in Japan like the Dura Ace ones to ensure shifting that's almost as quiet, quick, and precise as Dura Ace of course, not quite, but only barely. The battery used on both systems is identical, however, meaning you can go thousands of miles between charges on average. This groupset isn't cheapened by a lower end chain or cassette, either you get proper Ultegra 6700 bits, and an Ultegra standard bottom bracket is included, too. The 6800 crankset stands out as a beautiful piece of engineering, too. Once again, using Dura Ace as its inspiration, there is no comparison between the prior iteration of Ultegra and the new crankset. The 5 arm spider is absent and in its place is a 4 arm crankset, which not only matches rigidity of Dura Ace while saving 26 grams of weight, it also is compatible with both standard and compact chainrings. Gone are the days of needing two sets of cranks for two sets...