Two completely different classes of lathe. Note the different gear boxes. Note the D1-4 vs D1-5 spindles. Note the larger bed casting of the 1440 and two bolt tail stock end vs single bolt. 1440 all the way. If you go 1340 you may be required to change your name to EastLACowboy and your license plates to Colorado. Unless you move up to monster class lathe, a Kingston, Mori, Whacheon I'm in the buy a new lathe camp vs used.
As for mills what you plan to machine AND the work cube you need (X, Y, Z travel) AND the material you plan to machine (aluminum vs hogging steel) AND the spindle RPM you require AND how many feet in all directions you plan to fling chips are some of the things to consider.
I went full TEXAS on my mill this time around, bypassing knee mills altogether and stepped up to a 5hp CNC bed mill with a 40# taper spindle and box ways. Because
GET SOME!
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