I personally use tri-tronics, and dogtra. I feel thetri-tronics has served me better, because the only problem i have ever had was the charger, The dogtra has shut down on me in numerous situations, when super cold outside. I was halfway interested in sport dog, but everytime that i have seen them displayed or talked about the representative never had a dog to display with the collar. Tri-tronics and dogtra reps always had a dog. So i feel they can talk all they want, show me something while working a dog. These examples were at retriever hunt test, so we got land and water. Show me why?? I am not against the collars, I think they will work fine, have not heard anything bad. But have not used on any of my dogs. Thanks Jonesy