Thanks for all the feedback guys. A lot of really great info. I was originally thinking I might be able to work the price a little bit (given the groupset was the only change between the 2 builds), but it seems like the $1k is a pretty reasonable premium to most.
I've got Di2 on another bike and had honestly forgotten what the price dif was. But I do really love the shift speed/consistency + the ability to link up to my phone/bike computer. Totally agree it is probably a "nice-to-have" for 99% of people.
I will say though the other really intriguing piece of Di2 for me has been the "set it and forget it" component. Most people I know who have had it for years, myself included, say there has been virtually zero maintenance to worry about since the day they got it.