Not from a collector's point of view, but as someone who uses his mowers for their intended purpose, it's one of my favorites. Reasons: it only weighs about 45 pounds, simple, great old D-series engine. Mine was "custom" built long ago with a D570 engine from a snow blower so it runs about 800rpms faster and has an extra bearing on the crank, but the D400 is mostly the same and still one of the best. The magnesium deck is lighter and stronger than aluminum and doesn't corrode as easily. It's just a great combination overall. I have an older model that's basically the same configuration (5239A) and it's awesome too. To each their own, I guess.