IMO the differences that I am aware of are relatively minor. It seems to me the question with the two tractors you mention should be related to the cab and horsepower difference. Do you need/want a cab or the extra power of the 3720. The cab adds comfort but at the cost of some visibility and the added concern of damage if for example you are maneuvering through a wooded area.
My opinion, get the 3720
My opinion, get the 3720
