If you can find one in years from '06-'08 I.M.O. these are the best years. Many will disagree with this but this is why I got my 2007.
First, it has the largest YANMAR 1.1l same as the JD2305.
Second, it has a live front axle which I feel is stronger than the hydro ones. Larger tractors all still use a drive shaft so I.M.O. again there has to be something to this or it's cheaper for the hydro front AWD.
Third, as of now the new X758s can't take a loader and if and when they do add one it's going to add more cost and be pain to put on and take off.
Fourth, JD had to cut weight in 2013 they DID make a thinner gauge steel frame, but also used the YANMAR motor to be part of the frame.
Fifth, will say on the positive side, I like the new decks, but that's it. If you read this please understand it's just my opinion and others have a right to have theirs.
Sixth, JD still make the best garden tractor out there, but also how many are left making these? Simplicity? maybe more but that's all I can think of. If you can get a used one and save.
Thanks for your time.