I had a 2005 KJ with the CRD for 150K over 8yrs. That things was a tractor with the 242 Transfer Case and 545 Tranny. We went everywhere in ALL WEATHER. We even had it with 2 kids during car seats and stroller timeframe. The wife hated to get rid of it and the Grand Caravan that replaced it has been fine, but not the Jeep. She still is a bit mad at me but she is not mechanical at all. I opted to move it along as we neared 200K, since it would need a timing belt and at that mileage the head should come off to replace the valves. We regularly got 30mpg+ and with the tune and del it was even better. If you can find a well cared for diesel they are great, but orphaned these days so you have to WANT the diesel.
My parents bought a 2006 CRD after we bought ours. They put a tranny in around 180K and it now has 250K+ on it. I've warned them about the head and valves, but I think they are just going to run it until it blows. Rust is starting to show pretty bad.
As to the KJ part, as mentioned the cloth seats ALWAYS show water stains. Sweat from a soda will leave a mark on the seat. Window regulator clips are a common issue, but there is a metal upgrade available. The rear wishbone has a bushing that needs frequent replacement. But in reality just buy a new wishbone as the hole wears over time. The front driver footwell is pretty narrow if you have big feet, I prefer a stick but was glad this was automatic. Overall you sit straight up in the Liberty, more so on the back. But ergonomics and site lines are pretty good.
