At least on the Di2 system, there’s no long’ish lever action, so no need to push as far with the bigger levers to get to larger cogs or big ring. Easy button push and done. On mechanical there are click points as the action allows multiple gears depending on how far you throw the lever, thus there can me miss shifts if you press too far. With electronic, you can hold the button to move the range, do multiple presses quickly to move a few gears, or a simple push for a single gear move, thus no misses, in my experience.

I’ve never needed to reduce chain pressure to shift. The Di2 system claims to shift better under load. I’ve done lots of shifts while standing, never a lag or issue. The rear does a slight overshift on the derailer move ( the way you could on older friction systems) thus gets the chain onto the desired cog quickly. That’s a faster action generally. I actually have to look at my gear indicator to see if the shift happened on my Di2, it’s that quick and silent. Oh, and I get a gearing readout on my Garmin screen. That eliminates needing to glance back at the cassette to see what gear I’m in.

The front self trims as you move thru a cassette, something I have to pay attention to on my 9 spd. systems. No big deal just nice.

My 5800 front shifter was as good as any front I’ve used, the Di2 is even better. Once adjusted you don’t ever drop chains as well going down a ring. Kind of makes you wonder why the move to 1X.

Lot of little things that add up to an opinion from Di2 users that they will never go back.

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