The reviews contradict each other because two completely different products are sold under the same words, and the listing rarely says which one you are buying.
Radio direction finders. A small tag and a handheld receiver you carry. No network, no subscription. The handset tells you a direction and a rough strength, and you walk until it gets stronger. Tiny, very light, battery measured in months.
Cellular trackers. A device with its own mobile connection that reports a position to an app. This is the one that shows a dot on a map, and it is the one that needs a subscription, because you are paying for a SIM. Heavier, and battery measured in days.
Now your first question answers itself, and the answer is the opposite of what the marketing implies. For actually finding a cat that has not come home, the radio one is usually better. A map dot puts you within a rough radius of where the device was when it last had signal — and a stuck or hiding cat is typically under a shed, in a garage, or somewhere that radius is fifty metres of dense back gardens you cannot walk into. You end up standing in a lane looking at a dot. The direction finder keeps working at exactly that point, gets stronger as you close in, and does not care about signal.
Where the cellular one wins is the other question: where does she go, over weeks. History, ranges, which gardens, whether she is being fed three streets away. That is genuinely interesting and it is a different purchase.
I ended up with one of each and the honest split is: the radio tag lives on the collar permanently, the cellular one comes out when I want the data.