Just had my phone completely glitch out and is no longer working. When I tried to reboot the phone, it hung on the apple logo. I tried to restore to 11.0 and nothing. It still hangs. Drove 3 hours to the Apple Store and they had to send my phone off because it was flagged. So, now I am waiting on another phone.
I personally believe that there are some resource management issues with iOS 11, that start translating into hardware issues. I heard a tech today at the Apple Store tell a customer that software issues can only cause software problems, and can't be fixed with hardware replacements. That is not true. It is possible to overuse, or misuseI the hardware resources. For example, it is possible for a user to configure a computer to use a higher level of performance from its processor. This is well known as "Overclocking" the processor. However, that could cause it to fry if you do not have the cooling system in place for that type of performance. So I believe something with iOS 11 is causing a similar issue by misusing the hardware resources. I was having weird issues like my bottom speaker going out, but the earpiece speaker working. However, the glitch that killed my phone was while I was talking. It make very loud noises from the earpiece. Since then, it was lagging and then at reboot, it would not working any longer.