Rebuilt VS used engine on 2002 Jeep Liberty

Reasonably low mileage used 3.7L V-6 engines seem to be running about $2000 on http://www.car-part.com in my region. I’m assuming it’s a 3.7L for two reasons. Most Libertys have them, and most of them fail all too early. (Why they did away with the Nash 4.0 I’ll never know.) You can find cheaper engines, but why put a 120K engine in your car? At that mileage it’s probably nearing the end of its life too. You don’t want to do this again next year. That says to me that the $3500 installed price for the rebuilt engine may be the way to go.