In my opinion, which you will see is not worth much to many on this forum, if both units have the same engine series there is no difference. A Kohler Command is a Command engine, period. Now if you are asking if there is a difference between a Command, Courage, Magnum, Command Pro, Courage Pro, Aegis, Triad, K-series, yes there is a difference. Simple answer, you get what you pay for in the different series. It would take way to long to try to explain the differences. I would be more concerned who build the mower than who built the engine. John Deere is going the route of many of the equipment manufactures and having MTD build their low end mowers. Take a look at JD, CUB, TORO, they all look the same, except for the color of paint. Those of us who have been working on small engines for more than 20 years, would love to see the old John Deere, Toro/WheelHorse, Cub Cadet, Bolens units come back. They all built quality units, with transmissions, drives and engines that are 1000 times better than what they are putting out today. Don't know if this answers your question, but it's the best I can do without a longer disortation.