I used to give people the benefit of the doubt when they said there are "no issues" for them. Not anymore.
My friend and I were debating about iOS 9. My side, iOS 9 is quite messy, considering what Apple promised us back in June. They said it would be smoother, and it isn't. At all. His side was, "it's butter smooth. Perfectly fine." I argued back, "No.. I've tried out iOS 9 on your phone and it was awful.", he shot back "Fine, then we can work this out tomorrow when I show you that my phone is butter smooth."
Sure enough, he showed me. Doing tons of different things right next to me, from going in and out of the app switcher, from using control center, to using spotlight... He claimed "See? It's perfect!" All I saw was lag/frame drops. It was bad. He's using a 6 plus by the way.
Some people just *do not* see frame drops as well as others. And that's the reality of things.
Yes, I've done a DFU mode, set up as new install on my iPhone 6 and iPad mini 2. I can guarantee there are no installation issues.
On the bright side, closing apps with the multitasking gesture on iPad is now smooth when a keyboard is open, using control center on the lock screen is smoother (iPad) because "Slide to Unlock" disappears, and the "first unlock" lag after starting up the device is not nearly as bad. So iOS 9 isn't all awful after all.