Had the second and third gen Gizmos, maybe the first as well. Forget which one we started with. Most recently the third gen had horrible battery life out of the box. You could see it drop over about 10-15 minutes while sitting idle. Found a Verizon post to make sure the software was updated to add a battery fix. That took care of it. Real time tracking also eats up battery life. It normally pings the location and updates, but if you want to watch the kid walk in circles live it's gonna drain pretty bad. You can turn on/off real time gps thru the app if you need to pin down location for say school pick up and use the "regular" setting for geo fencing.
Used one for a stepkid and just got one for 9yo grandkid. Biggest problem was getting them past the novelty for the first few days when they'd call everyone every ten minutes to say hi. School mode also fixed it.
Nice thing is that if/when it gets lost, stepped on, dog eats it, etc., I think it's like $100 maybe? And nobody wants to steal a gizmo. Charger is proprietary but I got backups, extra bands, screen protectors, etc easy enough on Amazon.
Also like that the kid has to go thru the preprogrammed contacts in the watch to text. Extra step for parents, caregivers, etc to add the app, but the kid can't add just anyone. If you get both kids one, they can message each other as Gizmo buddies. Texts are limited to a list of preprogrammed messages like I'm home, need to be picked up, I don't feel well, but you can also send audio clips. Kid used that a lot for mom says we're outta milk, or something beyond the basic ones.