The visual size comparison tool is also extremely handy for comparing something you're about to buy, with something you already have access to. It gives you a much better sense of how much bigger/smaller this thing is.
For screens I use displaycheck.
It was DisplayMate, not DisplayCheck. https://www.displaymate.com/mobile.html#Latest
Their display "shootouts" are unparallelled in my opinion. For example they look at colour accuracy not only at high brightness but also at really low brightness, where displays often 'cheat' by reducing the contrast when they reach the limit of their backlight dimming. Which significantly impacts colour fidelity.
They also do many other types besides mobile displays, I just linked to that as an example.
PS: Sorry for calling out Linux for his showmanship but I just dislike this generation of Youtube "celebrity" that appeals to the mainstream over getting out of the way of high quality content. The only one I really have time for is Dave from EEVblog. Despite being quite the showman he really has the brains and doesn't hold back on technical info.
Thanks for linking DisplayMate, at first glance it's something I'll be needing to dive deeper into soon.
(To be frank, I think LMG labs is very much inspired by what GN has been doing over the last year or two.)
I go with Gamer's Nexus if I want to know if a GPU used the wrong kind of thermal interface for their VRMs and what effect that has on core clocks second by second, backed by rigorous scientific benchmarks producing huge amounts of data, summarized in highly detailed graphs.
It's much more focused on enthusiast computer hardware, but Gamers Nexus[0] is doing good things in this space too. Their style is much more dry and data-dense than LMG's though, which isn't everybody's cup of tea.
[0]: https://www.youtube.com/channel/UChIs72whgZI9w6d6FhwGGHA