I've come from an XS, so this is my first experience of it, noticed someone in macrumors mentioned it was on the 12 tooIt’s been there since the 11.
I took a video on my son's 6th birthday, and you can see the reflection of all six candles!
Unplugged my phone at 7am yesterday, and when I plugged it back in at 10pm it had 44% left. Huge improvement compared to the first day, so presume all the OS caching is done now. Huge improvement on where my old phone was by the time I was done with it!