I love my Cherokee, I got a 1998 4L (high output). I wouldn't say it doesn't perform, it's pretty nippy and faster than a lot of cars out there, 0-100 in 9.1 seconds (top speed is limited to 180km/h though). It does use fuel but then it is a 4L 6 cylinder so that goes without saying. I get about 15L per 100km average, that's a lot less than a Toyota Hilux 2.7!
The engine and drive train (is that how it's written?) are legendary, tried and tested. The motor was nominated for best engine of the year back in the day. Just remember it is an import so spare parts are too cheap.
Off road ability is excellent, you can pretty much go where ever any other 4X4 can go.
I wouldn't say it's a perfect car but I've had mine for 2 years and love it more and more every day.
Edit: I just had mine serviced last week, cost was R2000. That is through my mechanic, whatever you do don't take it to Chrysler to service. They will r@pe you and take their sweet time doing it too.