I have (perhaps foolishly) updated to iOS 9.2.1, because I wanted the custom repetition of events option in Calendar. Now I have a whole new batch of bugs and "features" to get used to.
For example: I can no longer select text for copy in Notes without opening the note for editing.
Calendar still doesn't have the ability to copy&paste an event - to create a new (non-repeating) event on a different date from an existing event, but with all other details the same (eg: deciding the date of the next committee meeting at the current meeting).
When text editing, it is not possible to move the cursor to the end of a string that the spell checker thinks is invalid without the string becoming highlighted for replacement - whatever you do, except move the cursor away again, results in the existing string being removed or replaced.
I quite like the two-finger track pad, but not sure how much I will use it.
Selecting text in a post edit on this forum can produce some weird effects: the position of the displayed selection block can be displaced from the actual text - even off screen - although the actual text really is selected. For some things I have had to revert to the BB Code editor, because the selection process in the RTF editor was almost as vague as Android.
The double-home open apps management has gone weird too. Apps are now listed with the most recent to the right (it was most recent to the left on iOS7), and instead of the current app being at the focus when you double-home or four fingers swipe up (which is where you want it to close it), it is the previous app at the focus (when all you needed to do for that was four fingers swipe right).
Something that is annoying me is that the Safari navigation bar auto-hides. I know that gives more screen area, but I would rather it didn't and there does not appear to be a user setting to stop it.
At least the predictive text bar at the top of the keyboard is an improvement.