This was the final straw for me to move to Android. My 6S was unusably slow with iOS11. I'd rather this be something _I_ can control.

At the very least, the performance should improve if you plug in the phone, and it doesn't.

Edit: other thing I remember is that when I upgraded iOS10 at one point my battery _stopped_ being reliable. I was getting the unexpected shutdowns at <50%.

Another weird thing I had experienced: after every update, my battery percentage would be totally screwy. I'd burn from 100% -> 1% in no time, then sit at 1% for hours. Over charge cycles, it'd figure it out again, but that'd be reset every time I upgraded.

Edit 2: looks like I angered the fans. This is simply my experience. My geekbench scores were awful, so I was certainly impacted by this issue. I thought I'd done something wrong until this news came out.

Another anecdata:

Last night, I finally succumbed to iOS11 (the only reason I did was that I wanted to enroll in Heart Study, for which your iphone device has to be iOS11).

Indeed I had been pushing it away because I usually associate the word "upgrade" to device death when it comes to mobile devices.

But wow... it did not screw my 6S up. In fact, I think it's faster and 'zippier' with this iOS11 upgrade.

iPhone 7 user here and iOS 11 also made my device much, much faster.

My 6S+ was also literally unusable after the iOS11 update. 5 second hangs on some actions, jittery scrolling.

It improved after a few weeks. Not sure if it was an .x update that fixed it, or maybe it needed time to reindex (?) but it's fine now.

Except that it gets unbearably un-zippy. If battery life really gets so bad that Apple believes it will reflect poorly on their brand, then they could do in-store same day battery replacements. But that would cut into their profits wouldn't it.

You think they don't make money on $80 battery replacements?

Profit on the $80 is much less than profit on a $700+ new phone.