You did not say what type of JD wheel rake you are looking at. The old ones that just had short teeth on the outside of the wheel did not work very well at all. The hay had to be fairly light and dry for them to work. The newer ones that have the long teeth that go clear to the center hub will work very well. The wheel itself is just about the same on all modern wheel rakes. They frames and mounts are the only big differences.
All wheel rakes are just driven by the angle action with the ground. The difference in todays rakes is the angle of the teeth they lift the hay more than drag it. If you do not have too much down pressure they will rake fine and not put dirt into the windrow. The biggest advantage with a wheel rake is raking speed and gentleness on the hay. A bar rake that is pulled very fast at all will beat the heck out of the hay.
Now that being said, I am not a fan of JD newer hay rakes they are boughten off of another manufacture and they are lightly built. There are much better framed rakes on the market. Sitrex, M&W , NH, And CIH rakes are all made by Sitrex. Kuhn/Knight has a good rake now. H&S makes a good rake as well.
I would stay away from the winged type wheel rakes unless you have a very flat field. They are not great at following the ground contours. These rake are just a hitch/frame that is three point mounted. They are much cheaper than the V type wheel rakes that have there own carrying/gauge wheels.