hagak, your post was very helpful, in part because I have a di2 bike and did not know about some of the integration that is possible with Garmin.
But on the whole, these posts are kind of convincing me to stick with my Lezyne Super GPS. It's pretty bare-bones, and occasionally drops my HRM, but on the whole it works pretty well. Maybe I should just be happy with that.
If there's one thing that really bugs me, it's spending big money and then facing frustrations - like software glitches.