When Joomla 3.0 was released, it incorporated a lot of new user interface elements in the administrator. Compared to Joomla 1.5 and 2.5, it was a big step forward, in my opinion. The inclusion of Twitter Bootstrap did a lot for the interface, but in the first iterations of Joomla 3.0, it was a bit immature.
Now, with the release of Joomla 3.2, the interface has been reworked quite a bit. Nothing revolutionary, but little things in many places, to improve how you work with the administrator. As one who has built large sites with Joomla 3.1, I think these improvements will be very helpful and time-saving.
There are improvements to the various lists, to the module options views, and much more. One of my favorite improvements is the inclusion of front-end editing of modules and menu items. Huge time-saver! Also a great function for those times where you want your client to be able to edit module content, but not access the administrator.
Take a look at the below video, where Beat takes a look at the UX improvements in more detail.