Hey Brooke -
I love mine...I have one for Murphy and one for Mia. I usually walk them with the lock position on and when we get to the field where there are no homes and they like to go potty I let it out so they can go do their business in private.
Even if I do not have it on lock my babies are pretty good about being right in front or beside me. I did have to watch little Mia (the little spit fire she is)....sometimes she tries to take off after a cat or something so the lock position is good if walking on a street. Best case is just work with them so they know not to take off and walk by your side. I am lucky mine do that pretty well but I do like having the option of letting the roam a little more on these leashes when it is fesible.