Went from iPhone 11 Pro. My iPhone 12 Pro has been good the first day. I just listened to The Verge podcast and heard they talked badly about the battery life, but I can't understand that it's so bad... Anyway, I think most phones will use more battery the first couple of days before it stabilise.
Both my wife and I have seen a serious improvement from the X. She would almost always be below 10% at bedtime and now she has been over 30% every day even with the normal trying new things on a new phone phase. I normally ended around 30% and yesterday (first work day since the switch) was over 80, but regularly I have seen over 60%. Everyone proclaimed the sky was falling, but we are both very happy.
Battery seems okay, trying to keep in mind that I set up as new in Sunday when I got the phone then restored from a full back up of latest public beta.I am hoping things settle down by the end of the week. Ending each day with any where between 20%and 30% left. But I'm definitely not using my phone like I usually do either since I always have a smart battery case on my phone.