I rented a prius and drove it to jacksonville to pick up my new car. I got pretty good gas mileage on the highway. I think it was reading around 45mpg and I was cruising at 75-90mph.
I would never buy one, because their brakes are horrible. I had the back end of the car swerving when I tried to stop for an accident that occurred up ahead. It was pretty scarry. I don't care what kind of gas mileage a car gets if I don't feel like I could safely stop or slow down.