The update is reportedly more stable than the problematic 4.3 update for the Galaxy S III, which along with the Note II launched with Android 4.1.2 last year. Samsung decided to skip 4.2 and go straight to 4.3.
Anyway, the update is rolling out in stages, so don't worry if you don't get it immediately.
You can use Samsung Kies on the PC or just check for updates on the Galaxy Note II itself through the About section of the settings menu.
Here's a changelog of the new features, which also includes support for the Galaxy Gear smartwatch.
- TRIM support
- OpenGL 3.0 Support
- ANT+ Support
- Samsung KNOX Implementation (KNOX bootloader and dedicated application)
- Samsung Wallet comes pre-loaded
- New GPU drivers
- Improved RAM management
- Improved Display colour reproduction (Display looks much sharper than before)
- Improved TouchWiz Launcher (Much less launcher redraws and less lag)
- New Samsung Keyboard
- New Samsung Browser (Full screen by default, new tab interface and more) and other apps
- New Reading Mode (Optimises display for reading, used by only a few specific applications)
- New Camera firmware, Sound & shot
- Minor UI tweaks (Contacts app, Flashlight Widget, dialog boxes etc)
- Android 4.3 features – widget lockscreen, daydream