I know they are classified as residential mowers, but are the engines commercial grade? Are the Mini FastTraks and Regular FastTraks both residential or are regular FastTraks better? Will a FastTrak do some serious cuttin' or should I go for something with a better commercial warranty. The Hustlers are expensive, but the commercial ones have insane warranties. Are Encores and small Gravelys any good? I just want a small ZTR.