iOS 14.3 has been about for a little over a month now and battery and performance has been so-so on my 11 Pro. Feel free to reply with your issues or comments!
No problems here with both an 8 and 11. Battery performance has been good for us. I just use my 8 for calls and texts but my wife is on YouTube watching videos for several hours a day.
I stayed away from iOS 13 completely on my iPhone X due to all the issues people seemed to be having with it. I did run iPadOS 13 on my iPad and it was fair but I experienced many issues others complained about that Apple never addressed/resolved. iOS 12.4.1 was very stable and performed very well but I wanted the new features offered in iOS13 and iOS14 so I knew I'd have to upgrade to the latest version of iOS eventually. I decided to buy an AppleWatch series 6 around Christmas so I had to update to iOS14 to use the watch and it has been a very positive experience so far. Battery life and performance have been very good even though my iPhone X has 83% capacity left and I have no regrets updating and look forward to future improvements..
Having no issues on my iPhone 7 Plus, iPhone X, iPhone XS Max, iPhone 11 Pro Max, and my beautiful Pacific Blue iPhone 12 Pro Max. Very stable release, however, I hope the next watchOS version fixes battery drain.
And since iOS and iPadOS are very close to each other, iPadOS 14.3 is running great on my two iPad Pro's, iPad Mini, and iPad Air.
On an 11 ProMax (AT&T)
Was okay. The nagging little bugs - nothing earthshaking or stopping you from using the phone.
More of the occasional pita than anything.
I love iOS 14, and iPadOS 14. Very happy it has the tracking prevention built in as well as the ability to completely shut off the COVID-19 exposure notifications. Don’t want that on any of my devices, and a friend has a rather new Samsung and cannot shut that off at all.