I have used the combination bit for both eventing and hunting. my 17hh ottb used it for a few months on cross country when he didn't quite understand the whoa factor and barreled around the course. it is fairly mild to begin with and still not too harsh when you "have to mean it" on a whoa. it was enough that after a few months, he switched back to a snaffle for cross country..we do novice but were to move up to training this year but an injury (wire in tongue) stopped that train til next year.
for hunting, i like it with him because he does pull alot more on the hunt. I like to use it because i can ride on a really light/loose rein and if he starts pulling, its much easier on my arms (aka, not exhausted by end of hunt) it's not much to ask him back, so he lays off the bit. he doesn't get too upset if i need to do a hard whoa, but he listens. It also is mild enough that I can ride with some contact and he's just as happy as a long rein.