If I was buying a sports car like a Porsche, Ferrari, Corvette, etc. I wouldn't even consider an automatic. Manual transmission for those types of cars all the way.
But for a Jeep that is used on tough trails, go automatic. The torque converter inside an automatic provides 2-3X greater low-end torque for things like crawling up & over tough obstacles. And also for those tough climbs and low-speed controllability, the automatic's torque converter helps there too. While there is a 1st gear ratio for automatics, you can't compare it to the ratio of a manual transmission. Again due to the torque converter which gives what is effect an infinitely low 1st gear ratio which means you can crawl over a trail at speeds much lower than a rig with a manual transmission can. You can go as slow as you want without killing the engine.
I even converted my first TJ from its OE 5-speed manual transmission to the 32RH automatic. The benefits of having done so on the rock crawling trails my TJ is most often on never ceased to amaze me. Smoother assaults on tough obstacles, no need to stab the clutch pedal to keep the engine running, more low-end torque, better control due to the lower speeds I could drive at on the tough stuff, etc.
So if you want to really do the tough trails, go for an automatic. All the top competitors at championship level events like the King of the Hammers run automatics. Four years in a row an automatic equipped Jeep won the EMC class at King of the Hammers which has both high-speed dry lakebed racing as well as the toughest rock crawling in the road.
Here's what the inside of a top-level rock crawler looks like... take a close look at its transmission shifter.
