Tons of good options in the used enterprise market. 3-5 years old, usually some paths for basic upgrades, as well as a flood of part availability from all the other similar systems being off boarded that were broken and not resellable. Laptops can be a bit roughed up, but full sized and sff desktops are usually in great condition.

User replaceable battery. Just like the DS, little cover with a screw. Makes it so much easier to keep old hardware working well.