There's a bunch of changes in this new release, obviously. The Nautilus file manager has received some love, including some user interface changes. Nautilus now also has a split view (finally), and now no longer defaults to spatial mode, preferring browsing mode instead. Yes, vanilla GNOME still defaulted to spatial mode. I love spatial mode - don't get me wrong - but the rest of the world doesn't. I was surprised it was still the default.
Empathy, GNOME's instant messaging application based on the Telepathy framework, has also been updated. IRC support has been improved, and a new information bar will popup when an account fails to connect, including a nice reconnect button.
Managing users has also been made easier, the developers claim, for instance by integrating PolicyKit into the relevant management dialogs, so you no longer have to mess around with the unlock button. There's more to this release than what's mentioned here, of course, so have fun digging through the release notes.