The Mii icon in the upper left seems to be changed slightly. Previously it would have an orange background if you had no internet connection, blue if you had one. Now it's clear and has a Nintendo Network icon in the corner which I assume means you have a connection? Not sure.
The Gamepad Alerts seriously just sounds like your gamepad will randomly play a ringtone and turn the screen on with a banner ad. Nice try, Nintendo. I've set mine to not play a sound or turn on, but to flash the home button. I'll leave it that way unless the alerts prove to be more meaningful than banner ads. I also sleep in the same room as my Wii U so I'd rather not have it turn on the screen and play a sound while I'm trying to sleep anyway.
Miiverse startup seems a lot faster to me. A few seconds instead of 15-30.
Still awaiting folders, controller support for Wii Mode, and the ability to boot to Wii Mode without requiring the TV be on.