I have Ultegra 6770 with an internal battery, my wife has 6770 with external battery. I like that it is virtually trouble-free, no adjustments, flawless fast shifting, and I never think about my drivetrain: it just works without anything other than cleaning and oiling. My wife has some arthritis issues in her hands and found mechanical shifting caused some issues for her and she now praises her Di shfting because it places no stresses on her hands. Battery life is great so no issues or problems there.