I reviewed quite a few OnePlus phones this year — the 8/8 Pro and the Nord — and most recently, I've been using the 8T. At first glance, I wasn't expecting much. It's a "T" phone so it's not supposed to be a major upgrade over the regular 8. But after using the 8T for a few weeks, I'm now sure it's a much bigger leap from the regular 8 than I expected. I even like it more than the iPhone 12 in some ways.
The best feature the 8T has that the iPhone 12 doesn't is a fast refresh rate display. Compared to the iPhone 12's 60Hz OLED display, the 8T's 120Hz OLED blows past it when it comes to responsiveness. Scrolling and swiping around is perceivably snappier and adds to the speediness of the phone. The 8T's 120Hz is also a jump over the 8's 90Hz, though the difference between them is less noticeable.