I give the 2008 limited 5.7L a 5 out of 10.
I call it the "Bankruptcy Edition".
At least I haven't been stranded. It's not that I don't understand Grand Cherokees. The 2008 is my 4th Grand Cherokee and definitely the most problem-prone. Others were 1997, 2000, & 2003 I-6 with Selec-Trac and trailer tow package.
Think I would get a JK Sahara Unlimited if it could be ordered with Selec-Trac drivetrain (like my ZJ & WJ's).
Bought the '08 new in October 2007 and it has 106K miles on it now. It is very well-maintained and passed the 5-yr powertrain warranty inspection without incident (except dealer found the rear driveshaft u-joint & pinion seal failing and replaced it). Only significant mod is the BT oil catch can. No off-roading.
Lots of issues I've had to repair or get repaired with my drivetrain, suspension, engine, and transfercase.
Here is what has been replaced so far (mostly under warranty):
Instrument Gauge Cluster – twice
Junction block / relays (driver’s side under steering column)
Multi-function turn signal stalk
Clockspring in steering wheel
Radio Head Unit - 3 times
Radio Driver’s door speaker
Radio multiple software re-flashes
Driver’s door master window/lock switch
Driver’s door window regulator (and module re-flash)
Driver’s door lock assembly
Tailgate latch assembly (and repaired grounded wire in harness)
Tailgate interior light assembly
Park Assist Sensor
Engine radiator cap
Engine serpentine belt – 3 times
Engine serpentine belt tensioner
Engine EGR valve
Engine EGR valve head-to-valve gasket
Engine MAP sensor
Engine O2 sensors (1 replaced at 22.7K miles; all 4 replaced at 53.7K; all 4 replaced at 61.4K miles; 2 replaced at 69.7K miles)
Engine exhaust manifold gasket (driver’s side)
Engine exhaust manifold, studs, nuts, and gaskets (driver’s side)
Engine exhaust manifold, studs, nuts, and gaskets (passenger’s side)
Engine exhaust Y-pipe and both catalytic converters, bolts & nuts
Engine cylinder heads (both driver’s side & passenger’s side), head gaskets, exhaust manifold gaskets, valves, springs, and keepers.
Engine fuel injectors (all cylinders)
Engine multiple PCM re-flashes and TSB's
Engine PCV valve
Transfer case rear seal
FDCM N23 reflash (recall N23)
Rear differential seal
Rear drive shaft
Shock absorbers (4) and 1 replacement @ RHS front after 6K miles
Heater / AC auto control instrument panel module
Heater blower motor
FOBIK’s (Jeep recall)
ESIM sensor (fuel tank evaporative emissions)
Passenger’s side outside rearview mirror
Rear brake rotors and pads
Battery (after 5.5 years)
This list is just excessive for a $40K vehicle.
Chrysler paid dearly for this and would have been better off replacing it under lemon-law provisions. I offered but they declined (stupid corporate policy).
The good news is that the last 25K miles have been as routine as the first ones should have been. Now that it is running well, I keep it that way with the lifetime powertrain warranty.