The updated settings module is similar in scope to Nokia's check storage Settings app module, although it does not offer the same app by app break down of memory usage.
With regards to new ability to delete temporary system files, it is worth noting that is routinely done automatically during normal use of the device. Earlier versions of Windows Phone 8 had a bug that meant this process did not always operate correctly. While this was fixed in the GDR2 update, the ability to manually start the process is a useful extra, especially if you are running short of storage space.
New storage settings in Windows Phone 8 Update 3 (GDR3) make it easier to free space on your phone and manage temporary files. A category view enables you to see what is taking up space at a glance. Each category also has a shortcut to a related page or hub for managing those files (e.g. Photos hub for photos). This new feature is Microsoft's equivalent of Nokia's storage check settings module.
More on Windows Phone 8 Update 3 (GDR3)
We covered the key new features and updates added by Windows Phone 8 Update 3 (GDR3) in our original news story. The update will start being delivered over the air to existing devices next month. However, developers and interested consumers can get early access to the update through the Windows Phone Developer Preview Program.
In terms of the consumer roll out of the update HTC and Samsung devices are likely to get Windows Phone 8 Update 3 first. Nokia's Lumia devices will get the update a short time later, a result of Nokia's plan to include a number of its own updates and enhancements alongside the Microsoft update (i.e. as with the Lumia Amber update, Nokia will be delivering a significant firmware update on top of the Microsoft update).