A good designer's work is subtle; it doesn't let the personality of the designer overwhelm that of the designed product.
An example of an automotive designer whose style was overwhelming would be Chris Bangle (http://www.wired.com/autopia/2009/02/chris-bangle-le/, http://www.motortrend.com/features/112_0601_chris_bangle_bmw...), whose work at BMW was highly distinctive -- so distinctive that it became quite polarizing. Bangle's design language was so striking that it was easy to lose sight of the personality of individual cars he designed; their "Bangle-ness" was the most visually obvious thing about them.
An example of an automotive designer whose style was overwhelming would be Chris Bangle (http://www.wired.com/autopia/2009/02/chris-bangle-le/, http://www.motortrend.com/features/112_0601_chris_bangle_bmw...), whose work at BMW was highly distinctive -- so distinctive that it became quite polarizing. Bangle's design language was so striking that it was easy to lose sight of the personality of individual cars he designed; their "Bangle-ness" was the most visually obvious thing about them.