The iPhone 8 Plus has a great screen for my needs, which include light phone use, IM, and a lot of reading on the go (IPS-matrix and 401 ppi resolution). With small fonts, especially italics, the typical figure eight already has a grainy appearance (resolution 326 ppi). As the new xs and xs Max used a PWM-enabled AMOLED screen, I rejected them right away (it starts to flicker at low brightness, which is critical for me - I read mostly in the evening in semi-darkness). Details can be found in the reviews on ixbt, so head there to read up. XR is also out of the question because, although having an IPS matrix, the screen resolution is lesser (326 ppi) compared to the 8 plus, and the screen is thinner, making it uncomfortable to read on.
When compared to the iPhone 6 Plus (which was upgraded to iOS 10 and given a brake device, so it's nice that it didn't upgrade any further), the iPhone 8 Plus has a faster app launch time (iBooks, instant messengers). A tvOS profile from Apple has been installed on the 8 Plus, bringing the software version up to 11.3.1, which safeguards the device from future ates and ensures that the device's performance will be stable moving forward (after the artificial slowdown of phones, I no longer play ates with Apple). I believe that, for the best possible experience, iPhones should be kept on their original firmware at this time. I'm not interested in the new firmware's emojis or whatever else is there for no reason other than to increase speed. Googling "block iPhone ate, install tvOS profile" yields relevant results for our investigation.
It has a battery life of a couple of days, and the camera is adequate for me, even though I use a 6 Plus.
TouchID can be used quickly and easily regardless of how you hold your phone, making it superior to FaceID in speed and convenience.
Superior build quality, sleek look (which some may find morally outmoded, but I buy a phone for myself and not to impress others with).
I haven't had any problems or reboots, but that's to be expected with a smartphone these days.