Beta 5 works ok on iPad Air with a clean install. The difference in performance and smotheness is not as visible as on iphone 5 lets say, but the potential to be faster than 7.1.2 is there, which is good.
Kind of dissaponting that apple didn't continue to make ios9 more responsive in some areas. For instance in this scenario: when you have 4 or more apps in app switcher, close an app and tap on the homescreen rightaway nothing happens, you have to tap the second time to get there.
If you do the same thing with only one app open the responsiveness is tremendous and miles better than any iOS up-to-date.
Hopefully apple will carry this speed all the way across the OS.
It seems like apple gave up on an interruptible screen unlocking animation (like in iOS6) a long time ago, where you could swipe the home screen before the animation has fisnished. Thats when iOS7 felt instantly "dull" in comparison, let alone iOS8.
Its a very small thing, but the one that makes your device instantly more responsive. They have it on iPad as "pinch to homescreen" gesture, but never carried it over to homescreen for whatever reason.
Anyways, after a year on half assed iOS8, iOS 9 in general looks very promising.
Yeah and in the betas so far this doesn't work also. When pinching you now need to wait again for the animation to finish. I really hope they don't forget it.