I've had a couple of JKU's.
The first I only had a month before an idiot crossed the center line on me and totaled it out.
Funny enough, it was the 2007 2wd variety, and my plan was to build it into a Rubi from all of the parts that folks were ripping off of the Rubi's of that era (around 2k9 timeframe). I remember seeing Rubi axles and associated equipment selling for next to nothing compared to what they're selling for these days on the JKowners forums.
The second was a Sahara that I had put a 2.5 lift along with some Nitto Terra Grapplers. I drove the hell out of that thing, and overall really liked it for the most part.
The things that really irked me though was the engine used oil to the tune of about a quart between oil changes every (3k miles). There were a number of anomalous electrical glitches that would shut down everything electrical in the cab for a few seconds. The worst was a stupid knock (sounded like a golf ball rolling around in the B pillar) that happened when the driver door striker got a little worn. The fix was to wrap electrical tape around the striker... seriously.
I did love them, in a restrained, "I HAVE 3 KIDS, AND CAN FINALLY HAVE A JEEP!" way, not in the I've got this TJ, and it's all mine kind of affair that I'm in now. Some people lust for exotic, or fast vehicles. I've always lusted for the dirty, go-anywhere, do anything Swiss Army knife of a vehicle that the TJ is. To me, the TJ still has that OG soul that the JK/U's lost just a little a bit of.