I really like the road ID interactive ones. They link to a profile with your information, any documents you want to store, etc. So I have the fact that I'm a service dog handler, and a request not to separate me from my dog on mine, and then the information for the service that they can call/look up to get my emergency contact info. There's a number/website and then a code on the inside of the bracelet plate. That way I don't have to have my name or condition hanging out on my wrist, but it's very quick and easy for someone to look up should the need arise.
My emergency contact also has the pin number to get into that file, which gives her access to my very basic medical info and other emergency contacts/my family member's contact info, living will, care instructions for my service dog, etc. should something ever go far enough wrong that she would need to access any of that information.
It's very handy and provides me a lot of peace of mind. Their customer service has also been amazing. They're designed first for runners/athletes but a lot of people use them as medical alert bracelets and they were very willing to help me sort out what might best meet my needs over the phone. I can't recommend them enough to people who need some form of security but may not fit into the standard categories.