It's all in preference. I prefer a collar because I don't think a harness offers very good control. (Unless they're swimming, then they have harnesses because when they shake their heads to clear the water out of their ears the collars rub a raw spot! :lol: ) Some people like harnesses. You're probaly going to have to try it and see for yourself. If you've got a puller, I'd NOT recommend a harness. It seems to make pullers pull harder IMO because there's no pressure on their necks, it's distributed differently and makes it "comfortable" for them to pull.