I like my TJ. I bought it for $5K almost 5 years ago with a little over 100k miles on it. It needed some TLC. I replaced the exhaust manifold, O2 sensor, plugs-wires, water pump, and the radiator. If you can find one that looks ok with no rust but needs deferred maintenance, then you can get a decent deal.
The inline 6 is generally preferred over the 4 cylinder in the TJ models. However, if you are not taking it on the highway much, the 4 might be ok.
The water pump was real a "while I was there" when replacing the radiator. The plastic top tank on the radiator cracked. It was plugged with gunk from a lack of fluid changes. I went to an aftermarket aluminum radiator. It was not much more expensive than the stock replacement. A little fab work was required to make it fit, but it was worth the piece of mind.
The exhaust manifolds are a known weak point, most of the aftermarket ones ate better than stock. They tend to crack and foul the O2 sensors and generally make the Jeep run like E36 M3.
My TJ has the smaller axles, Dana 30 and 35. This is not an issue with up to the max stock wheel and tire combo, 30 by 9ish, if I remember correctly. The small axles also shouldn't be a problem unless you go to big tires and/or start rock crawling. I am in South Carolina so I see a lot of the same terrain: sand, red clay, mud... so no issues with a Sport.
The Rubicon and Sahara had Dana 44s. The Sahara may only have the 44 rear axle on some years. The lockers on these higher spec models are really the selling point for mud and sand terrain. The Rubicon has the heavy axles and lockers at both ends.
Look the frame and undercarriage over for rust. These things can rust pretty badly if they have been up north for any length of time.
TJs are easy to work on for the most part. The engine is super easy to access. The axles are pretty reasonable to service. The only gotcha from my perspective is the integrated transmission mount and skid plate. The mounting bosses for the skid plate are glorified nutserts and tend to spin in the frame. This can make dropping the transmission for clutch work or seals a prolonged experience. You can do fluids without dropping the plate, so routine maintenance isn't really effected.
All the parts and then some are available!!! You can literally build a new TJ Jeep out of a catalog and a stack of cash. As an example, the rear window on the soft top is a wear item that you can buy without buying the entire top. At the other end of the spectrum, I am pretty sure that you can buy a complete body.
I will say, after taking care of the deferred maintenance the TJ has been a solid semi daily driver. Some weeks, I drive it every day, others not so much. It pretty much depends on the weather. It also does a nice jop towing a small utility trailer for yard work and runs to the hardware store. It also parks like a sub compact when not hooked to the trailer.
