Canonical recently released Ubuntu 15.10, nicknamed Wily Werewolf. In the past, an autumn release of Ubuntu Linux like this would have been more experimental, warranting some caution when updating. Such releases weren't quite update-at-your-own-risk rough, but they were often packed full of new features that were not fully baked. (For example, the now-shuttered Ubuntu One first debuted in 9.10. The Unity desktop became a default in 11.10, and the controversial Amazon search results in the Unity Dash made their debut in 12.10.) Especially compared to the spring .04 releases that tended to be stable (and every two years packaged as Long Term Support releases), autumn was Canonical's time to experiment.
Unfortunately—or fortunately, depending on how you feel about desktop experiments—that's not the case with Wily Werewolf.
There are new features worth updating for in this release, but, on the whole, this is Canonical refining what it has already created. The organization is essentially getting ready for the next LTS release (Ubuntu 16.04, due toward the end of April 2016), which will also likely be the last LTS release based on Unity 7.
So by this time next year, 16.10 will bring back the experimental new features with an entirely different beast on the desktop. Look for Unity 8, Mir, and other big changes to return in next year's .10 release, re-establishing the fall as Canonical's playground.
But talk of Unity 8 and what it means for Ubuntu can wait—we should first appreciate Ubuntu 15.10, which might be the very last of its kind for a little while. This is a stable, welcome update that doesn't require you to radically change your workflow or habits.
While Ubuntu 15.10 is unlikely to win any awards for innovation, the kernel update includes some very useful new features, a couple of UI changes for Unity, and plenty of application updates. All of these make the new release well worth an update.
The most notable UI changes are the scroll bars, which are now pulled straight from GNOME 3. Canonical has abandoned its little disappearing "handle"-style scrollbars in favor of GNOME's defaults (which have improved considerably since Ubuntu started work on its own version). The change appears to be based more on code maintenance and development effort than any strong aesthetic feelings from Canonical. Writing and maintaining your own scroll bar code may be more work than it's worth. The visual change is minor and solves quite a few bugs in Canonical's home-grown scroll bars, making it a win for users as well as the programmers once tasked with maintaining the old code base.
Abandoning the homegrown scroll bars might also mean that Unity is able to integrate upstream GNOME updates faster than it has been lately. With this release, most of the GNOME suite of tools that powers much of Unity have finally been updated to 3.16, though a few holdouts like text-editor GEdit remain at much older versions.Ubuntu 15.10 review: Wily Werewolf leaves scary experimentation for next year