Web browsing on the device is better after the update, thanks to the improved HTML5 compatibility on Internet Explorer. And stability is improved for VoIP apps like Skype and Lync. In addition, the GDR3 update adds a FM radio to the phone. You will need to use an earphone to get the radio to work, since it acts as the antenna. Group Text is now available as a messaging option, and while it is off by default, you can turn it on using the correct toggle switch.
Other parts of the update include a series of apps that make it easier for the visually impaired to use the phone. The device will read information about calls and texts to help those with trouble seeing the display. In Driving Mode, you can decide whether or not to receive notifications about blocked calls or texts, and a orientation lock will keep your phone in landscape or portrait mode. Bing apps for finance, sports, news and weather are now supported. The app comes out of the box on new phones, and can be downloaded from the Windows Phone Store for existing users. For multitaskers, press and hold the back key to see a list of recently opened apps. You can access any of them by tapping on the app, or close one out by tapping the "X" on the right corner.
The update is coming OTA and if you haven't received the notification yet, you can try to pull it out of your phone by going to Settings > Phone Update > Check for Update > Download. The download will take 10 to 20 minutes and the installation should take another 10 to 20 minutes. During the latter, you will not be able to use your phone.
source: Verizon (1), (2) via WMPoweruser