The MTH is a more accurate representation of the style of ore jenny used by the Great Northern, so that is my preference. In a comparison of detailing between the MTH and the K-Line jennies, contrary to what others have claimed, the level of detail is similar, the primary differences being the interior rivets, which you don't see with the load in place, and the lack of stirrups. The K-Line lacks the air brake detailing.
Great Northern Iron Ore Car 89446 at Kelly Lake, Minnesota… | Flickr
GN 91612 Mineral Red Ore Car at Allouez, WI in August 1979… | Flickr
MTH Premier car on the left, K-Line car on the right:
MTH:
