Persistent notifications for apps running in the background. This is new and kind of annoying - apps that run in the background and didn't used to show up in the notification area are now there. For example, my favorite Network Monitor Mini Pro, which has a setting to not show an icon in the notification, now started to in 4.3.
Google Wallet was doing the same. There is, however, an easy solution to this - go to the app's info page and uncheck Show Notifications. Problem solved. See below for some screenshots. Never mind, this doesn't stick - the notification comes back after rebooting, even with Show Notifications unchecked.
The Master Key exploit, at least according to Bluebox's own Security Scanner, is fixed, as we expected it to be.
The dialer finally has T9 dialing. You need to first enable Dial pad autocomplete in the dialer settings though - it's not on by default.
Bluetooth Smart (BT 4.0 LE) should be enabled.
AVRCP 1.3 should also be on now. Song info in your car via BT. Exciting!
There is a setting to keep Wi-Fi on at all times for positioning purposes, even when you disable it.
New camera and gallery, which were previously leaked from the i9505 dump.
The dump comes with a new Play Store v4.2.3.
Google Keep is now included as a system app. See below for a screenshot.
There's a separate Fused Location apk now. I'm not sure how it's different from the fused location functionality in
Google Play Services, but hey - it's there separately now.
I'm sure there are more under-the-hood improvements (hopefully, some Wi-Fi and BT fixes at a minimum) and features I'm too tired right now to hunt down.