Some of you may know that I am using an iPhone 4s temporarily because I broke my 5s about a week ago.
I upgraded the 4s I'm using to iOS 8 this afternoon, and the performance of the 4s feels about the same to me under the new operating system as it did under iOS 7. It is not quite as fast, but it is still definitely usable.
Overall user experience is better, because there are new features of iOS 8 that are accessible by 4s users. Examples are:
- standard iOS 8 keyboard with QuickType,
- the "Hey Siri" feature,
- Notification Center widgets,
- Recent and Favorite contacts in the App Switcher.
I think the best illustration of limited iOS 8 functionality on the 4s is the Messages app screenshot I published at the top of this article. Although the keyboard looks good, and QuickType works, there really isn't enough room for text entry and display of the current message thread.
If you get in this situation on a 4s, send your message quickly so you can see what your friend / relative / colleague is saying.