As usual, the genuine belt is a little more expensive but it does the job, the only reason for the '4-star' rating (well, after thinking about what a pain changing a belt on any mower can be, I decided the durability of this belt, despite the extra cost, was worth '5 stars'!.) I find they last a long time, longer than other belts used on my other brand lawn mowers so can't say it's just the belt or is it 'John Deere' technology in how the belt is arranged on this mower. I will say the JD mower has been worth the extra money! This is the first belt replacement on this mower since purchasing it used ten years ago, I don't know how many hours it has in total but I'm impressed it's been this long compared to other mowers I've had!
When you're changing the belt that's not all you're doing. Be sure to check the 'blade brakes' and when reinstalling any removed nuts I recommend putting 'white lube' on the threads to make removing them next time MUCH easier. As you can see, there was lots of corrosion on the mower deck on this used JD I bought a few years ago, but the parts are still solid. Find the diagram in your manual or check online if you don't have one (as I didn't purchasing a used one) so that you know how to put it back together, especially if you're replacing a belt that fell apart and you have no clue where it goes!
Finally, there are TWO belts on this mower, one for driving the blades, one for the transfer of power to the transmission- be sure you get the right one!