That really depends what your plans are for the vehicle. I have a 02 WJ and I love it, 217,000 miles and it still runs like a top. I'm partial to the 4.0 motor, but the V8's are fine motors as long as they've been treated right. Check to see if the coolant is green or red, it should be red. If it's green that means the previous owner doesn't know how to properly take care of their vehicle.
If you plan to lift it at all, then you need to take a look at the front driveshaft. If it has U joints at both the diff end and the t-case end, then you've got a good one, if it has a rzeppa joint at either the tcase side or both sides, you're going to have to replace the CV yokes and get a new driveshaft with U joints at both sides. The rzeppa joints are a great design for stock ride height, but with any lift they can't handle the new driveline angles.
I can't tell for sure, but something looks off with the brush guard. Not sure if it was installed wrong or if it's been hit, but something looks off on it. Also in regards to the brush guard, you're going to want to take it off anyways as the brush guard mounts to where the factory tow hooks are installed. As the vehicle is right now it has no front recovery points. You can get a set of factory tow hooks from a junkyard for $10 and 10 mins of your time, they're a super easy install.
Also take a look at the shifter indicator bezel inside the jeep to see if you have a 242 or 247 transfercase. The 242 is prefered as it has 2wd, 4hi locked, 4hi unlocked, and 4lo locked. The 247 only has 4hi unlocked and 4lo, so you'll be in 4wd all the time.
If it has a check engine light on, there's a trick where you can cycle the key from ACC to RUN 3x and it'll flash OBD2 codes on the digital odometer. Google those codes and see if any are particularly worrysome, this is also a good way to knock the price down a bit. Same thing if the trunk, rear glass, or hood struts are worn out, ask for $50 off the price per pair that won't stay up.
If it has the dual zone climate control make sure the heat and AC work on both sides. The blend doors fail on the DZ climate control easily and you have to pull the whole dash to fix it, it's a **********.
The rocker panels like to rust on these jeeps, especially with a michigan vehicle, I'd be on the look out for rust, but I'm sure y'all are used to rust up there.
Jeep sold a ton of these during their time, so spare parts are easy to find as long as you have a junkyard nearby.
The one thing I'll leave you with is do a little research on the jeep 4.0 i6 vs the 4.7 V8, they both have their pros and cons. If you do decide to go with the V8, I would definitely hold out for an overland model with the 4.7 High Output motor. Yes, it's a jeep trim package called "overland", you'll see an emblem on the side where it says "limited" on the craigslist one. It's essentially the highest trim package there is and came with factory rock sliders, factory tow hooks, a high output motor, and every creature comfort they offered.
This website will tell you just about everything there is to know about WJ's
http://wjjeeps.com/jmenu.htm
And here's a pretty conclusive buyers guide over on jeep forum
https://www.jeepforum.com/forum/f310/ultimate-wj-grand-cherokee-buyer-s-guide-1271979/
I'm in a hurry and haven't proof read this so sorry if anything is mistyped. Let me know if you have any questions, the WJ is an awesome vehicle, but they have their quirks.