Kannad Aviation FAQ
First, you may not have a choice, as either a PLB or an ELT may be mandated in your country, so check your local regulations.
If you have a free hand to choose, select an ELT if you want an automated rescue alerting system which can call for help even if you are unconscious or a PLB if you are happy to rely on manual activation. Remember that a PLB has no way of calling for help if you are unconscious.
If you want maximum security, select both – an ELT for your plane and a PLB in your pocket.