Originally Posted by rm -rf

The biggest Di2 advantages, for me:
3. I have the rear set to "shift 3 cogs with a long press" (which is about 1/2 second or longer, instead of the usual "mouse click"). So, at the base of a hill: hold down the bottom buttons on the front and on the rear. That's shift to the small chainring, and shift 3 cogs smaller in the back. Rolling over the top of the hill: hold down both top buttons -- big chainring and 3 cogs larger. Both shifts at the same time, no need to do the rear and then do the front.
.