Note 2 user here:
Scrolling - is generally smoother on iOS, there can be no doubt about that. I literally get a little shiver of joy whenever I pick up my 4S just because the screen follows my finger so precisely.
But I still prefer the sheer speed of Android scrolling. Whether I'm going up or down doesn't matter, I can get all the way in just a few quick swipes. This gives me a greater sense of being in control than what I get with iOS.
Screen rotation - this is one of the most irritating things with Android for me, at least on my Note 2. I hate waiting that extra half second (sometimes whole second or more) for the screen to rotate, compared to my 4S which seems to follow my command much better in this regard.
It's better since the 4.3 update though. At least now the screen doesn't get helplessly stuck in the wrong orientation anymore
Text selection - I use to loathe the way this was implemented on Android, but since the 4.3 upgrade I've not had those issues with the markers going haywire anymore. I actually rather like how this works on Android now, with the cursor ending up exactly where I want surprisingly often, even at the first touch when quite far zoomed out from a long text document. The markers are kind of ugly though.
Copy/paste - this is a breeze since I started using Swype. Swipe from Swype symbol to C = copy, to V = paste, etc. It works extremely well and is very fast and intuitive, and uniform across all apps. I absolutely love this, and miss it dearly whenever I use my 4S (and swipe typing in general, of course).
Keyboard bug (stays up) - this almost never happens anymore for me since the 4.3 upgrade. When it does however, Swype again comes in handy. Swipe from the symbol to Backspace = lower keyboard.
As for stuff not already mentioned:
Watching Youtube clips from other apps - this is utterly horrible on my Note 2, don't know how it is on other Android phones. Basically, I press the link and pray. Most of the time it is very slow to start, and when it does it usually refuses to rotate when I flip the phone over. Fullscreen normally doesn't work. And the whole procedure usually leads to the app crashing.
Whereas on my 4S this is remarkably smooth in all respects. Not sure how Google can just leave this in its current state. How is this on other Android phones?
Notification light - I love this in principle, but I really dislike that I have to wake up, unlock, and pull down the notifications tab before the light stops blinking. There should at least be an option to have it stop as soon as I've just woke up the phone - which should be sufficient confirmation that the user is now aware of the message/reminder.
Again, not sure how this is on other phones. Maybe TouchWiz is the culprit for these last two points?