my advice is, buy one with the largest screen you can get for it, that will fit where you want to mount it,as you get older, them smaller screens become useless, IMO< unless your young and have great eye sight!
I won'r say I am any expert on things,
but from my experience and from friends that added them to machines,cars, trucks, (HARD WIRED NOT WIRELESS models)
they all the makes models we used all seem pretty much the same, in quality, prices have varied from pretty cheap to higher end ones, and we haven't seen any stand out differences in images or likes, and all we set up still work(longest might be 12 yrs or so)
the one I installed on my skid steer back in like 2017 or so, I got off ebay for like $75 bucks I think if memory is right, but it was pretty cheap,
, and it was a plug and play deal, , with a male Cig lighter plug for power (does have inline fuse on it too) and I already had a female cig plug in cab!
so I just had to run wires to camera and screen, and mount camera and screen where I wanted things, and it was installed, about as easy/simple as could be,
it still works, but the screen is so small,(4.5 inches or so) I seldom turn it on or use it, as my vision isn'rt what it used to be.
IF you work in a very dry dusty environment, you may have issues with lens getting coated with dust and require cleaning often, so, keep that in mind when mounting it! so its easy to get to to clean!
I am sure the higher end models, maybe have more features and clearer screens, but I don;' think there a MUST buy/have for most users!
a basic cam is fine for most, I'd try and stay with screens above 7 inches, to me screen size bigger is better as long as you can fit it!
and again I'm no expert, so just my 2 cents here!