A used Prius could be OK, but more likely has been traded because the previous owner had some issues with it. Also, as mentioned, there is no certainty how long the battery will last, since you don’t know the car’s history.
You can buy a new Hyundai Accent or Honda Fit for the same amount as a used Prius that’s a few years old. That will give you good gas mileage, good reliability and low operating cost, and you don’t have the $3000 battery replacement bill to contend with.
In other wors, a used Prius is OK if you personally know the ownmers and know they have maintained this vehicle by the book, and it has turned out to be not a lemon.
Forget about the accelerator/brakes panic. That would never stop me from buying a particular car.