The width of the box blade depends on how you are going to be using it. For heavy work such as excavating, heavy grading and moving large amounts of soil the 5' unit would work better. For light work like grading the driveway, small leveling projects, etc a 6' would probably be ok. You just don't have the weight or traction to pull a 6' in a heavy cut with the rippers down. I agree on the 5' bush hog as well.