Bay Alarm Medical makes an “at-home medical alert” and a “go anywhere” medical alert, and a smartwatch medical alert. The company seems well regarded in reviews on the Internet, and these products often score well in on-line review sites of medical alert products.
The company has a solid reputation as a home security company (ie burglar alarms etc).
Like many medical alert providers, the company outsources the actual “monitoring response service” to a company that specializes in that service. In the case of Bay Alarm Medical, they use a well respected monitoring responder company, also used by many other medical alert providers, called AvantGuard.
This vendor is a good place to start in any search for a medical alert.