Just like with old school CPR, there's really no guarantee you won't be a vegetable. Maybe you get lucky and the person doing CPR does it right, the AED arrives soon enough, and the paramedics arrive soon enough. Always make sure you have a living will to cover such kinds of situations. I would hate having my vegetable body ending up in a fight between loved ones who want to keep me alive and loved ones who want to do the humane thing.
Here in Denmark there's a volunteer "heart runner" programme. If someone calls 911 and has a cardiac arrest, people in the programme that nearby can be notified to fetch an available public AED and run to the patient (or attempt manual resuscitation).
According to their material, the 30-day survival rate in Denmark has gone from 3.8% (2001) to 10.4% in 2016, with 67.5% bystander assistance: https://hjertestarter.dk/english/you-can-save-lives though it's not clear how much the programme itself can claim.
According to various papers, rapid CPR/AED after a heart attack can triple survival rates.
It's still pretty bleak outcome, but better than e.g. in 2002 Detroit, where 1 out of 471 out of hospital cardiac arrests (OHCA) survived to hospital discharge. In USA, all those stats are apparently being tracked by a programmed called CARES.
