I'm finding the performance of my 6s extremely unacceptable after the iOS 11 and 11.0.1 updates. All apps are slow to respond, and Apple native apps seem to be the worst culprits. Mail is almost unusable. It hangs up whenever I open the app, and I have to restart it multiple times a day to get it to be responsive again. I'll often archive an email, and it immediately shows back up in my inbox. The phone app tends not to show my latest voicemails. I have to restart phone app to get the missed calls/voicemails to show up correctly. Everything is just frustratingly, doggedly slow.
The battery hit is major, not as minimal as others are reporting. I had the battery replaced early this summer under warranty because I had a faulty unit that would shut off unexpectedly. For a relatively new battery, I'm way too reliant on my portable charger. I have to recharge multiple times a day to keep the phone from dying.
With these issues and the un-inspired flagship phone designs, this is the first time in 10 years I'm seriously considering an android phone. Hoping for something compelling from the Google Pixel 2 announcement. Apple's hardware and software ecosystem isn't what is used to be. The one thing I like is their commitment to privacy and security. That's the ONLY thing keeping me from going Android...because I'd rather not be tracked by an ad company!