Zero Turn Mower

Having a dealer nearby that has parts/service for your mower is important. I've had trouble getting parts for older John Deeres. Their lower priced mowers are built by MTD or others. There better models are built by JD and are good quality. Skag is the premium brand, but they are expensive. But they also have a high resale value if well maintained. Toro is a good brand.
Gasoline powered mowers would be my choice. Diesels have a price premium that requires many hours of operation to re-coup the investment. If gas, at the end of the season run it almost empty and add a gallon of ethanol free gas [$15 ?]. Run it for 10 minutes and store it for the winter.