My main problem is that if I simply want to do something on any iOS now as soon as I unlock it I'm blocked by pop ups for things like making a back up and buying more iCloud storage and upgrading to iOS 11 -- things I never intend to do. There's no way to switch these off either. And they happen constantly, multiple times a day.
Last time I used my iPad I dismissed a popup, opened up an app and the same pop up came a few minutes later completely interrupting me. I have no tolerance for these annoyances.
Samsung phones were complete trash back in the day with their bloated interface but I've since switched to a Note 8 and the experience has been very good. UI is very clean and the performance/features on the phone are outstanding.