The old ones wore out after 14 years and had to be replaced. I looked at many models made by many manufacturers, and finally settled on JD.
Nothing is this category is available from Kubota. JD and Caterpillar are the only tractor companies with this available.
I was very pleased that JD had these available. The three point quick hitch at the top is exactly what I wanted. The tread pattern is just right as well: good traction, but not overly agressive.
So far they have performed really well. I wish the decals said Kubota, but it is a real kick that at least they do say John Deere.
Never thought I'd be promoting a JD item, but this is one I give five stars.