2nd gen Prius a safe reliable buy?

Something I've always done is carry an extra quart of oil and collapsible funnel in any car "just in case". In the Prius they fit well inside the little well pocket under the floorboard behind the driver's side rear wheel.

 

You only need to use oil for high milage cars if your car is using a significant amount of oil, which Toyota defines as 1 qt per 600 miles.

Personally, I would look at oil for high mileage cars if I was using 1 qt per 2500 miles.

Monitor your oil usage and bear in mind if you use a high amount of engine braking (say, going down long mountain roads) you will use more oil than around town/highway cruising. If your car does not use significant oil, then stick with standard synthetic. Once you start using oil for high milage cars, you cannot general go back to normal oil.