Well, seeing all these good reviews, I guess I will give the other side of it.
I hated it for Ellie.
It "might' be okay for larger dogs but I even know of one who got a raw nose from the loop, so not so sure about that.
Anyway, bought it, watched DVD and put it on Ellie. Putting it on just right is very important and if it is done right, it should be very tight but not on an area of the neck that has anything to do with choking/throat/trachea... I was very uncomfortable with how tight it was (I don't care if it isn't going to choke..it is still her neck). Then when the dog pulled their head is pulled toward you. Fine if it is done right but it seems that that could cause problems/injury if you're not careful.
So, just get it from a place that you can return it and decide for yourself.
