Among the most notable new features is the added support for Google's voice recognition hotword. This means that whenever you say “Okay, Google”, Nova will launch Google's voice search for you. All in all, a pretty neat addition to the launcher's features, but be advised that this voice recognition does not support all Android devices or locales just yet.
Another spic and span functionality is the subgrid positioning, which allows us to snap items, such as icons and folders, halfway through the grid on the screen. Paired with the added capability to individually select each widget's padding, Nova Launcher 3.0 significantly steps up its game in the customization department. Speaking of widgets, customization devotees can now pin both 1x1 and 4x1 widgets to Nova's dock.
Last, but surely not least, Nova Launcher 3.0 is significantly lighter and even more stable than before – its memory usage has been slashed and the developer, TeslaCoil, has also fixed the most common issues that caused the app to force close. We can't be happier about this!
And here's the full changelog of Nova Launcher 3.0. Be advised that the features from the beta version are not listed here, but are still on board:
- Ok, Google - Google Voice Search hotword support
- Subgrid positioning - More flexible layouts by snapping items halfway through the grid
- Dynamic Calendar Icons - Supports Today Calendar's Dynamic Calendar Icon, also supported by icon themes such as Domo by kovdev or KEX by Phlash
- Color options -for icon labels, folder backgrounds, drawer tabs and background
- Show App Labels option for dock and drawer
- Colorblock drawer tab style, with individual color controls for each tab
- Backup/Restore using KitKat's Document Provider (Supports external sdcard and Google Drive)
- Full widgets in dock support (1x1 as before, but now with 4x1 as well)
- Individually toggle widget padding (long-press on a widget and select Enable/Disable Padding)
- Fix adjacent pages showing in landscape on some devices
- Fix drop in place of icons moving down the grid
source: TeslaCoil via Reddit