I have narrowed my search for a new mower to one of the two frontmounts -Grasshopper 722D with Kubota diesel or the Grasshopper 729 Kubota gas with a 61" deck. I doubt a person could go wrong with either of those, they seem so meticulously designed. However, the two mowers are pretty close in price, with the 722D being about $400 more by the time it's all configured. Hoping any of you with experience with these mowers could comment on the engines. As I have read here, it seemed that the Kubota engine used in the 729 was basically derived from the engine used in the 722 mower. I started both of these mowers in the dealer showroom and could not believe the quiet and smoothness of the 729 Kubota. However, the 722 is a diesel, with obvious benefits of longevity and low fuel consumption. Engine life between the two models is probably a mute point. Any comments here either way? I am looking for adequate power to drive the 60" deck at speed, along with good fuel economy. Thanks in advance for your feedback.