I personally think crawl control is gimicky and I would rarely use it, but you have to admit it's cool. I used it a couple of times on my landcruiser to show off to buddies. I'll never forget the first time, sounds like all hell is braking loose and things are going crazy, but that is it. It's rapid braking and accelerating, doing all the work for you.
The best terrain for crawl control is going through rocks. In deep mud it's useless. I've not tried it in other terrain other than those two.