pretty good summary here. I've had a 90 and a 95 both with the 4.0 and the one in the 95 screamed that thing was one great performing little SUV
one of the cons is hte price for an unmolested one, they can fetch a good chunk of change for a nearly two decade old vehicle
To wheel them does get expensive and you always have to worry about the stupid unibody. The HP30 is a great axle that can be built very easily and can sustain serious abuse, avoid any XJ with a D35 rear end as those are known to simply blow the r&p just driving on the street. Ask me how I know....
Look for a 8.25 rear end I think they came in mid 90's and newer XJ's, it was chryslers replacement for the d35 and is much more stout
Reliability is an 8/10 especially if you know how to turn a wrench, these things are very very basic.
Snow driving is a 9/10 if you have some decent siping on your tires, the wheel base and obvious 4 wheel drive make this thing a staple of the northeast for a reason...
On road driving? It's a fucking jeep...2/10
Keep your eye out for any 96-99 XJ's they are widely considered the best but 91-99 are also good buys