On the other hand, I feel all you do is trash Apple, or be dismissive of other opinions. Did you see my post where I gave an opinion of iOS 8? was that sentence skipped? iOS 9 was an instant improvement on my iPad 2.
And I am entitled to my opinion same as you.
If you think I trash Apple then you probably never heard of me on these forums. I owned a lot of Apple products, I really like what this company make. However I'm tired to decide between more features or better performance whereas before I would just hit the "update" button and everything was fine after that.
I don't expect my device to work as good as it was after 5 years of usage but seeing worse performance and bugs after only one major upgrade (less than a year) is a big example of poor optimization.
Think about iPhone, iPad and Mac sales declining and don't tell me that Apple isn't getting worse and worse these days.
People have always complained about Apple, of course they do there is no "perfect" company but in the past people were complaining about how iOS started to look outdated or how Apple control everything in iOS but they never ever complained about performance, stability or reliability.
And by the way, I need to clarify something. I have no complaints about how iOS 9 run on my iPhone SE and iPad mini 4. I can see the occasional lag or hiccup but it's rare and doesn't bother me at all because it's nowhere near the lag fest that my old iPhone 5s was on iOS 9 (which was perfectly fine when I got it on 7.1.1 by the way).
So why am I complaining about performance ? Because not everyone have the latest and greatest iPhone or iPad from 2015/2016 and because I know that my devices will eventually become trash if I upgrade them to iOS 10. This has happened before multiple times and I have no doubt it will also happen at the end of the year.
And to finish, may I ask you something ? Are you using reduce motion and/or increase contrast on your devices ? This may explain why you can't see the lags and stutters on iOS 9.