I've found cooling to be drastically improved with the CSF radiator. We pulled Homestake Pass in MT with out camper this summer. I had the trans in 3rd and the UZ spinning about 4,400 rpm (driving 55 mph) for several miles. The engine temps barley got over 200F and the trans temp never crossed 200F (though the TCC was locked). I was in the fast lane passing semis. That radiator is worth every penny.
When off-road I find the engine runs much cooler if I put it in a lower gear. If you are crawling in low-range 2nd or 3rd and lugging the motor, it will get a lot hotter than putting it in a lower gear and spinning the engine at 2,000 rpm or higher. I think it's due to having a mechanical fan that doesn't move a lot of air at idle speeds, as well as the water pump also moving less water.