I picked appearance, because the tail lights are what first made me want a Bonne. But comfort would be just as, if not more, important. I just like the comfort (interior and ride) you get from a bigger car.
I voted appearance since that was what put it over the top when deciding between it and the Aurora. But really the Bonneville is such a complete package. I can't comment on quality yet, but this car really has it all: Looks, decent performance for a sedan, comfortable, loaded features, good stereo, and a great ride. All this in a very affordable price as a used car.