I rebooted a couple times after installing, including one with power + volume down.
Scrolling through the settings menu seems smoother than ICS, as does scrolling between screens, although swiping to the left to access the quick settings page feels as if it has a slight jerk to it.
I feel as if Chrome scrolls through pages a little smoother now although it could be my imagination.
Also in the category of "could be my imagination": I took a few pictures of a fairly dark room in the early morning, and I felt as if the camera was able to handle the darkness better than before. That could just be in my mind though.
The swipe-up-from-home to access Google Now is neat, although it seems redundant with the google bar that's built into the OS.
The voice questions seem to work fine - tried "where am I?" "what time is it?" and..."Where is FAO Schwartz?" and it worked well.
I haven't gotten any notifications to test the new notifications yet (except for app updates, which don't seem to do anything different unless I'm not doing it right).
The lock-screen clock is on the right side of the phone instead of the left, haha. And it shows the date and alarm there too, which I don't think it did before.