I agree, training has got to be the biggest part in this equation, then the type of harness/collar. Ultimately do we not want the dogs to obey what we want them to do, as supposed to have a gear that forces them to do what you want them to do?
Yes, training is key. But not all animals respond the same way to the same thing. Sometimes it is trial and error as to what works best for which dog. In my house, it is individual even with the types of treat that work - Ruby prefers cheese, Brando beef liver, and Liyah chicken. IMHO, same with collars and leads.