I bought the 2008 Yaris 9-14-07 and went on vacation. 44 mpg on the interstate, 41 mpg city and interstate. 3500 miles and not one problem. Am I happy. The only thing I didn't like was when you drive on dirt roads, the rear fender wheel wells have no guards and the road noise is bad.
Gas mileage is great and the duel trip meter makes it a snap to monitor gas mileage.
The wheel wells on the rear need plastic guards to prevent wear and noise. and maybe some undercoating. Bells and whistles I don't need, road noise isn't needed either.