depends on the engine really?
2.3l Duratec was fine, although it was designed for transverse mounting, so has a nasty little coolant line on the back of the engine, you have to drop the transmission to get to it if it starts leaking.
3.0l Vulcan was just at the beginning of the Valve seat issues, '04-'06 TSB, also rash of bad coils in early 2000's
4.0l SOHC had timing chain issues until '05/'06, but if they were changed under warranty, or changed by PO then they will be fine, the new design works fine
Any engine will go bad if not maintained, and used is used, even with records you don't have the history or the "oops" factor, an overheat or low oil level drive
'03 has "Live axle" in the front so no auto-hubs to F*up, a good thing.
5R44E/5R55E automatics are OK, but are automatics so when they go it gets expensive, check and smell trans fluid.
4x4 module behind radio is a common issue after 2000 model year