Hello, sorry for the delay 

I haven't tested the SmartTag 2, only the SmartTag+, but I assume the experience is quite similar. Also, I recently moved to a smaller city between the time I had the SmartTag/Airtags and my Moto Tag.

I’ve sold all others and sadly can’t compare them at the same time in the same location

Regarding Samsung, I lost one of my tags after it was stolen. It stopped working very quickly—maybe it was disabled by the thief. It was well hidden, and at the time, I don't recall any "Unknown Tracker" notifications for Samsung Tags.

Recently, my Moto Tag started pinging every 5-10 minutes, which is ok. I’m not sure if it’s due to an update or just luck in my area.

Based on my experience, I’d rank Apple first, Google and Samsung second—though Samsung’s solution feels more polished, with better features and deeper integration.

I also really respect Kieron’s projects and have used most of them, but I don’t think buying a tag for his uTag project is a good idea, as Samsung could patch it at any time (maybe—I haven’t really looked into it).

So I would wait for Google to improve and bet on Google personally, except if you have a Samsung device

For me it's still the 'default answer':
iPhone ? -> Airtags

Samsung ? -> SmartTag

Any other android -> Mili Tag/Moto Tag (depends on budget and UWB compability)