you can go to www.tractortips.com and get the weights and horsepower for the John Deeres. Search here and get the same for the Yanmars. If memory serves me right the YM 2500 is very simular to the JD 850. I don't know if any use the same engines or other parts, but there is some parts interchangability. It has been my experience that the simular sized tractors handle about the same, but I have not used that many different ones. I believe that the John Deeres are built a little wider and heavier than the Yanmars of simular HP.