For the price, I really can't complain. Have had some build quality issues, but they are all minor. It does make a lot of engine noise, and tire noise is also annoying at times- but then again, it is an econobox. I hope to get at least 200,000 miles on it before any major repairs have to be done. I sense that Toyota has slacked off on some of it's products, but I think the Yaris is worth the buy.
Cup holders are cool. Just right for a commuter car. Fits easily into a parking spot.
Better seats would be a help- my back usually hurts from the cheap and lack of cushion. Reduction of engine noise and tire/front end noise would be a great help. Noisy cars tend to make people nervous, as if something is wrong. Use a little better material to make the interior.