The TJ compared to the JKU "off road" is interesting. The TJ SE has nothing in the way of computer assistance on it, and the JKU has a ton of goodies that "help" you drive under various conditions. My SE doesn't even have anti-lock brakes. The JKU has anti-lock brakes, traction control, a stability system, hill decent and at least one more nanny control that escapes me at the moment. When you take the TJ out, you just drive it to the best of your abilities. It goes where you point it and does what you tell it. Not necessarily so on the JKU.
Lifting a JKU or even putting larger tires on it changes the inputs to the computer and also changes how it reacts. Most of the changes are subtle, and barely noticeable, but they are there. One example that comes to mind is when the wife was learning how to hill climb on a loose surface. The traction control was actually fighting her. With the traction control on in 2wd the JKU would bog down and try to dig the rear tires in. In 4hi, it was better but still noticeable. It did OK in 4lo. Most of these nanny systems can be turned off once you learn the routine, but shut the rig off and you have to do the dance all over again. Each selection in the transfer case has a different program for the nanny systems in the computer. That can be a little disconcerting at times as the JKU reacts differently than you were expecting depending on 2x, 4hi or 4lo. Even just going above the tire size that came stock on a particular JKU has a pronounced effect on performance. That's both on road and off road. My best advice is to budget in a good programmer if you decide that a JK/U is going to join the stable.
We're still playing with the JKU off road, and learning what it likes and doesn't like. More on this later if anyone is interested.