Jon this is an interesting topic, I was looking at my carpenter and smith handles the other day.
The up-lock on the smith makes the distance from reel to gimbal longer, which in theory increases leverage on casting, making casting of heavier plugs longer for less effort, some may say, but I'm not a physicist so correct me if I'm wrong. As we have discussed recently this handle length is effective to a point and also dependent on the build of the angler.
The other issue would be where most of the load is carried by the reel seat. In theory it would be on the front of the seat, with the fish pulling line off. If the un-threaded part of the seat is in fact stronger and more stable in theory it looks like Smith have it right. I may be completely wrong though.
