Initially purchased a John Deere x350 to replace an aging Craftsman with a 20HP Kohler that is still going strong but after 10 years and going through 3 decks, and countless belts and broken mandrels I wanted something more solid that did not have to be repaired after mowing almost every week. After trying out the x350 on my property it did not handle the slopes on my property very well and seemed to strain going up the hills. I live on a lake and the property slopes in tiers down to the lake.
After reading about the John Deere Promise on these forums and learning about the K46 I returned the x350 and ordered a x570 with the K72 transmission that I hope will handle my hills better. The Craftsman had a manual transmission and did not have any problems on the hills, just everything else on the mower was falling apart.