My neighbor just traded her 2001 Jeep Grand Cherokee in--within the past 3 years it needed a heater core (common failure on these,and requires the entire dash to be removed--cost her 1300 bucks)--then a few months later the alarm started going off for no reason at 2-3 am,local garages couldn't figure it out--dealer charged 780 dollars for a "body control module"...
The following year it started losing coolant,the water pump was blamed,another 550 bucks for a new one installed,but it still sometimes ran very close to the red line on the heat gauge..
2 months ago the dealer who did an oil change said coolant was mixing with the oil,and I checked the oil and sure enough--mayonaise!..she traded it in quickly before it started steaming out the exhaust...it has about 125K and she never used it for anything but driving to work and go shopping..oh yeah--it was the V8 version..!
At my friends shop,he has quite a few customers with these Jeeps (yuppie favorites around here)--he's replaced many automatic transmissions,transfer cases,quite a few front diffs,a few rears also--at least 4 of the V8 engines too ,that had valve seats drop into a cylinder,or the 4 foot long timing chains wear holes in the case and leak all the oil out & seized,many others needed radiators,water pumps,and a lot of them broke the rear shock bolts off in the unibody,and its a challenge to fix them..
He and I agree the "best" Jeeps have an inline six and if its a manual transmission ,so much the better..personally though I'm not a Jeep fan,if I had to have one,it would be a pre 2000 model with the straight six and a 5 speed manual..I feel their diffs are weak,and they are overpriced,for what they are...rather stick with an old chevy !.