Originally Posted by maust1
Size of the rear seat and rear doors and in most cases the bed. The quad has the smaller door, seat and the larger bed. As far as feature differences all I know of on the tradesman (the series I own) is rear seat air. I am sure someone can give you a more detailed description.
This sums it up. If rear seating comfort, ie. for tall people is important, the crew cab would be the better choice as it will have more leg room. On the other hand if bed space is the most imortant factor, but need the rear seating space, then you would consider the quad cab, as the bed is longer.