I just installed the same version on my bike six weeks ago. For me the best thing is 100% reliable and fast front derailleur shifts. I’m pretty good at setting up a rear derailleur, but no matter how much I fiddled I could never get a cable-actuated front mech to shift into the big ring nicely. I would always get that annoying thing where it takes a second extra for the chain to catch on the big ring, or if I had it shifting nicely it would rub. Plus, since it’s just pressing a button with Di2, I can easily change into the big ring from the drops since I don’t need to push the whole lever sideways.

With Di2 I haven’t dropped a chain and it shifts instantly, just whzz and it’s ready, with the automatic down shift at the back too. The auto-trim feature is great too, no rubbing at all.

Honestly I don’t have a bad thing to say about Di2 at all, I’m far from a competent mechanic and between my group set arriving through the door and taking it for a first ride it took me about two hours to install everything. Just to change the cables previously would take me an hour of fiddling around with magnets to try and get them routed through the frame.