This is a big update for iOS 7. It should bring quite a bit of stability and refinement to iOS, along with a few welcome features.
More than anything it is a ton of bug fixes, especially the dreaded home screen crasher that has been vexing me for the past 6 months.
It is a very welcome update, but it is a little shocking it took 6 months to fix so many of the glaring issues in iOS 7 in one big update than a number of iterative updates.
If you haven't updated yet, be sure to go and run Software Update from Settings after you do an iCloud or iTunes backup.