Apple released the third seed for developers beta testing iOS 7 on Monday. iOS 7 Seed 3 includes a number of bug fixes and improvements, as well as new features and tweaks to many of Apple's built-in apps and services.
Initial reports of iOS 7 Seed 3 show that Apple has indeed improved performance, including smoother scrolling, smoother app switching, and fewer crashes. Notifications perform substantially smoother, as does Control Center.
Update: Reddit user Noth1ngman posted an image of new animation Apple has added to apps that are installing or updating.
Install Animation in iOS 7 Seed 3
(Arrows & labels added by TMO)
Other changes:
Siri's voices were tweaked with "new development versions" to the male and female voices for U.S. English and French, and the male German voice. Apple introduced new Siri voices at the WWDC keynote, and included them as part of the second seed. The new development versions appear to be slightly tweaked from that seed.
Apple has fixed issues with sending music to Apple TV through AirPlay, though the company is still working on some issues. AirDrop also is being tweaked, and developers were told there were compatibility issues between Seed 3 and Seed 2.
iCloud continues to go through changes, too, with syncing issues being worked out and compatibility issues between seeds. This includes iCloud Keychain, and as with any beta release, developers should probably not put mission-critical systems on the beta. This is still early in the process.
Messages remains in flux, with some known issues and workaround present in this seed.
Summation
Apple is making remarkable progress in iOS 7 as it works to a fall release. As noted above, it's still early in the process, and there is a lot of work to be done.
We make that point for those anxious for iOS 7 to be released. It's getting more and more exciting, but we have a while yet to wait.