Silent is my preference but to each his own. Just seems like that open mouth would keep the hog out in front of the dogs. Around my way there is a lot of very thick cut downs that end up being 20 or 30 acres of briar hell. A dog don't have a chance of just flat footed running a hog down. So I think stealth mode is the best. Sneak up on em bay em bite em in the nuts if he tries to run. This works well for us.
X2... I have to admit, it is hard to find a good cold nose cur dog. Like you said, the good ones are not for sale...