Perhaps our favorite function with Di2 is shifting the front derailleur. It's light years better than any mechanical group and Shimano brings reliable Di2 technology and performance to Ultegra for precise and effortless shifting. This latest Di2 version is the R8050 and it's 11-speed compatible. The R8000 is slimmer so it plays better with bigger rear tires and sheds about 22 grams over the RD-6870. Blindfolded, we're not sure if we could tell you if a shift was executed with a Dura Ace or Ultegra Di2 derailleur.All mechanical derailleurs use spring and cable tension to move the chain from big ring to small ring and back. Shimano Di2 and this Ultegra RD-R8050 Di2 front derailleur utilize digital technology where an electronic signal is sent to a motor making the shift. Shifting is ultra-quick for launching a quick getaway before the competition even has a chance to react. Best of all, the performance is on-par with Dura Ace (it can actually be subbed in if needed) with the only real difference being the slightest of weight gains.As we stated above, front shifting is where the largest benefit of Di2 exists. Di2 front shifting is much faster than cable shifts, so you can attack over the crest of the climb where analog shifters are still fumbling with their gears. We really like that Di2 shifting effort is akin to clicking a mouse. Press the button once and the shift occurs. No more having to hold the shifter over and adjust your cadence, babying the chain up on the big ring which only gets worse as cables and housing deteriorate. Di2 shifts perfectly from day one and remains that way regardless of the conditions. Take a look at most of the Shimano sponsored cyclocross racers. They demand Di2 because it works in a terrible muddy race much worse than what a typical road bike would see. The auto-trim of the front derailleur is another feature that spoils us. The front derailleur automatically trims itself based on where the rear derailleur is, so that the chainline ...