"I see no compelling design issue that says an Avalon is "beautiful" and a Lucerne is "ugly"
A Toyota is very well realized, from the texture of the dashboard, to the "feel" of the switches to the way everything just fits and works together well. There have been precious few vehicles from GM in the past 30 years that could be described similarly with a straight face. That's the difference. I have never owned a car built by an "American" manufacturer, only Japanese, even though the last two were actually built in the US. I'd be happy to buy American, once the quality and performance are up to par. I thought the Chrysler 300C would do the trick, but all the hard plastic in the interior was very off-putting. They're getting close; they just need to realize that fit and finish extends especially to the driving environment. None of them really seem to completely have a handle on that yet.
After driving the Honda Accord, Toyota Camry, Nissan Altima and Hyundai Sonata, I ended up with a Ford Fusion. While each of the other cars had one or more features that were superior to the Fusion, they also lacked in other areas which gave the nod to the Fusion. I have the 221hp V6 with 6 speed automatic and I find it comfortable, quiet, and entertaining to drive.