I just discovered the joys of automatic draft-saving when I returned from a browser crash, to find my half-written post waiting for me!
I don't like way that the smilies list pops up under my touchscreen keyboards on phone and Tab.
I love the dissapearance of the constant resizing that was necessary before the changes.
I was reading the bottom post of a long page when an alert popped up. When I dismissed that, the page scrolled back to the top without any input from me, which meant I had to scroll back down again. That is not good.