after building/wheeling both (not high hp buggys)
Trail riding/booze cruise = auto
Rock Crawling = stick (with lots of gear reduction)
Hill climbing/rock bouncing = auto
I find that I prefer a manual in a crawler and 90% of the time on the trail, because it forces you to maintain momentum, i.e no crawl a rock-stop- crawl a rock- stop
If I'm driving an auto, I either want hammer down on it constantly and take advantage of the quick shifting...