I agree with others, properly fitted martingales are great, secure collars! But their use against pulling is limited. Some dogs don't like the pressure on their neck and are more respectful than they would be on a flat collars, but those aren't usually the dogs who pull hard enough to make themselves gag/cough on other gear. If you want to try it, and the dog doesn't have any health contraindications that would make pressure on her neck especially dangerous, definitely go with (or suggest the owners go with) a wide martingale, as opposed to, say, a rolled leather style, as this will help distribute the pressure some.
I've personally found the best success with physically controlling a pulling dog with a front-clip harness - not a no-pull version, just a regular, unrestrictive harness with a front clip harness (I have not personally tried head halters). Blue-9's Balance Harness is a good example. However, I have not had to deal with a puller as large and strong as many pit bulls are. If it's at the point of endangering the handler, dog, or other people/animals, I have no problem with using more aversive tools (like no-pull harnesses) short-term, until you're able to catch up on leash manners training enough for everyone to be safe on a regular harness or collar.