I just bought a Nexus 6, which came with Lollipop. It's an "upgrade" from my HTC one with KitKat. There are certainly some features of Lollipop that leave me scratching my head, but I'm more disappointed with the deprecation of features that I thought were otherwise brilliant.
The Do No Disturb in Lollipop, for example, has been "dumbed down" so that, instead of giving us flexibility in our schedules, like normal humans, we're tied into a schedule for multiple days, but for the same time range every day. WTF Google? I used to have a DnD schedule in KitKat for Monday and Tuesday from 2:45 - 4:15 and on Thursday from 3:50 - 5:20. Not with Lollipoop, er, Lollipop.
In KitKat, having the ability to arrange the apps on my home screen based frequency of use was a Godsend. I loved that. I also loved that I could vertically scroll my home screen to get to less frequently used apps. I didn't use many additional panes, but it was nice to have for some other apps and widgets. I
In Lollipop, I can't find ANY way to sort the apps. In fact, not only can you not sort them, if you move one, you have to manually move another to fill in the space left empty. While I suppose that empty space was previously filled by the auto-sort, I still don't like having to fill that gap.
I suppose over time I'll forget what I used to have and get used to Lollipop, but it doesn't make for an easy or transition or a happy one.