I quite like the Unity interface. I don’t really get the hate for it around the interwebs, and it seems like most of it is driven by a resistance to change.
However, my single biggest annoyance with Unity had been the odd way it handles switching between multiple windows of the same application.
Previously, you would have to click on the application icon in the launcher, and if you had multiple windows open, it would show you an Exposé-style view of the windows, and you would have to select one of them.
This behaviour was even applied in the Alt+Tab switcher! This made switching between same-app windows a colossal pain, as what was previously practically instantaneous had now become bit of a chore.
Now with Raring Ringtail dropping, this has been fixed.
You can switch between windows much faster by right-clicking the app icon in the launcher, where the options now include a window listing.
While Unity overall feel a lot snappier and includes some subtle visual refreshes, this is the one killer “fix” that makes the upgrade to 13.04 completely worth the minimal effort involved!