I can tell you who we went with when we were choosing and why.
We went with Medical Guardian. It was about $50 something per month because I went with the insurance on equipment(wisely so).
All responders are 911 certified with a triage of family contacts.
No long term contracts. (Watch out for those) and you want to be able to pay by invoice because getting those cancelled can be a nightmare on ACH.
Ours was a base unit. A pendant with fall detection. A locked door box with house key for emergency responders (combination was relayed to MG). A refrigerator card with all medications written down for emergency responders.
They do have various options for bracelet, cell, roaming. Wi-Fi or landline options. We needed landline. Our mom had a pendant. Which was waterproof. I replaced once at no charge to me.
Now the proof is in the service and return of equipment and how. Quickly they cancel upon your notification.
We tested that pendant numerous times. And they help you set up system while on the phone with them. Excellent service. Highly recommend. ( and I receive no kickback nor compensation for saying this).
The only problem we had was that the pendee would not wear it. We found it in such interesting places -- alas never on her.
I researched 12 before I went with this one.