I used it for about 4 years, then my oldest, and then my youngest. Such a great little piece of hardware.
As someone who has both I strongly disagree with that claim, though the 3 and 3T have certainly aged well.
This is really noticeable on more recent Chinese devices. Not only we have a +90Hz display, but I believe there's a focus on animation speed because some reviewers over there test how fast it is to open and switch apps. So we end up with something that is smooth and also feels fast.