The full feature list can be found on Apple's support pages.
This update weight in at 331Mb on my iPhone and 385Mb on the iPad mini.
The most annoying thing with this update is a new app that you can't get rid of: the Apple Watch app. Useful only if you have an Apple Watch! You cannot uninstall it like many other built-in apps, the best you can do is hide it in a folder along with many other space wasters.