Our X720 went into the shop after my wife mowed her sisters yard with and stopped for a few minutes to chat and it wouldn't start back. It was still under warranty and she was really ticked, called them and told them to come pick it. She had too much other stuff going on at the time to haul it her self. They claimed it had water in the fuel, changed the plugs, drained the tank, changed the fuel filter and air filter. Bill including picking it up was like $225, we brought it back home ourselves. Now we run non-ethanol fuel and Seafoam in every tank. It seems these EFI engines are pretty darn picky IMHO. We had a JD LA130 for about 3 years, never missed a beat, never spit, never sputtered, never surged. You would think a $9K mower wouldn't be so darn picky about fuel. We ran 87 10% ethanol in the LA130 all the time. She wishes now she had bought the diesel. It seems a bit better since switching to 100% gas but still surges when you first start it. Other than the engine it's great. If we trade we're going to take a real bath on it, believe me we've already tried. I think they offered $6200 for it with a 125 hours. This a dealer that she spends about $10-20K a year on equipment and parts.