I have one of the original Dura Ace Di2 which is very nice and never let me down; however, I am getting a new bike and have selected the mechanical Ultegra group set. I own another bike with older Ultegra and it also shifts like a dream so I decided to save myself some money and go with the Ultegra group. If you want the Di2 go for it as you don't really have to worry about the battery unless you just ignore it. You may want to ride both, if you haven't already. I'm sure you will enjoy either.