We looked closely at the Yaris 6.5yrs ago when we bought the Corolla, and the Yaris made no sense to me. Equipped with the "must have" options on our list (AT, AC, Cruise, power windows, keyless) there was a $700 price difference between the two cars. While the Yaris had a slight (very slight) fuel economy advantage, the Corolla was much roomier inside with a larger trunk and was nicer to drive. And yes, the Yaris is a typical Toyota in that it holds it's value well, but not as well as the Corolla. Long haul, the operating costs of the Corolla are less.
Also, back then, the Corolla had significantly more safety features. For the additional $700, it seemed insane not to buy the Corolla.