2002 has some problems, but are still nice.
We bought ours used, and unfortunately from someone who ended up not being very reliable. We've had a lot of problems with it: the wiring that controls the automatic windows has gone out, so the only window that works is the driver's side in the front. There's a problem with the fan for the heater, so the driver's side vents only blow cold air, and the liftgate in the back will not stay up by itself all the time, so you either have to keep something to prop it up, or just hope it does not fall on your head when you are trying to load or unload stuff. It is all stuff that is fixable, of course, and once those things are fixed, it'll be a great car. It is reliable, it runs well, and it gets great gas mileage. But, if you are considering getting an older grand Cherokee, make sure it is older than 2002, because those do not have all the problems with the wiring and heater going out.