Drove to West Branch, MI last weekend, round trip about 300 miles. Not bad.
First tankful out of the dealership gave no better results than my beloved Corolla, 31 mpg. The "computer", however, said I got 47 mpg. OhhhKayyy...
The tankful I put in yielded 50 mpg with no change in my driving habits, and the "computer" backed me up. I have no explanation for the initial discrepancy.
The tankfuls to W. Branch and back yielded an impressive 56 mpg. My only worry was watching the bars go down on the hybrid battery readout whilst stuck in "get out of town" traffic Friday night. I ran on battery power for about 45 minutes as we inched along. Ran into another jam on the way home with same results. As soon as we broke free, the CE started to recharge the hyb. battery and within about 15 minutes or so we were back up to normal.
My only complaint is that the ride is stiffer/rougher than my Corolla; and it likes to follow every groove in the pavement, yielding some fighting in the steering. The steering is waaay more sensitive than the rack/pinion I had in the Corolla--drive-by-wire is more like a motorcycle in that where the eyes go the car goes! I liked the way the Corolla "cornered on rails" as it were; I don't get the same impression with the Prius. It handles well, and is nimble enough, but just doesn't "feel" the same.
My normal commute is mostly highway except for the first and last two miles. My next tank I'll take surface streets and see what happens. According to all sources (Weathergirls!), my mpg should go up as the hybrid system was engineered to get better mileage in the city than on the highway. Now, my highway miles are all in the city, with corresponding stopNgo during "rush hour" (what a misnomer THAT is); so we'll see if there is any difference. More later. Apologies to those that use metric--you'll have to do your own calculations. I'm allergic to math.