I have the Iota Tracker which has served me well by putting one on my dog's collar when we're out in the park and it works well in NYC b/c of the mesh network. The only issue comes when I'm somewhere else and there isn't any coverage.
This gives the Guardian Orb a leg up by having the Guardian Go option so you can still utilize the tracker when you're not close to home.
The range is also what sets these trackers apart. Guardian has a 5+ mile rang via GPS. Tile only has a range of 200ft since it uses Bluetooth.
CollageMo