I have the Dogstra. It was recommended by the trainer.
I have BC’s, a cattle dog, and a lab. Have had Danes and sight hounds. Never felt the need for an E-collar until the lab. She came to us as a 2 year old with no training and no off switch (outside, fine in the house). Sweet but too much dog. Jumped fences, dragged on leashes, no respect for pasture fences/horses. I tried for a year but we were all miserable and frustrated–especially the dog–because she was unable to participate in hikes, road trips, trips to river, boating, that all our other dogs enjoy.
I did not want to train her myself. Did a lot of due diligence and found trainer that came highly recommended. Sent dog to her for three weeks with regular lessons for us and dog each week and opportunity for follow-up as needed.
What a success and head-banging I did not do it earlier. She can go off leash with the other dogs. Goes to the river to hang out. Got her CGC and passed therapy dog training tests along with the other dogs. I would never have attempted the latter without the relationship and confidence we were able to build after working with the trainer (who also worked on other basic skills w/o the collar).