It comes down to how much you plan on towing and how heavy you are. I have the 3. 73 gears with the HO 6-speed. I can't imagine having 4. 10's because mine already tops out real quick in the gears, even when towing. I only tow about 11K with mine but I have taken 6% grades for over six miles and never come below 65 mph. I also use mine for commuting 100 miles a day so the lower gears also help with the mileage.