I do like this collar a lot. I wish it had a sound volume control option and was a bit cheaper for the distance. However, for what I use it for, it works very well. Efficacy: I actually use only the sound option and my dog responds very well to it. I use it as a recall device mostly. When she barks across the property, I don't feel like walking all the way over to her to get her to stop but once she hears that beep, she stops immediately and returns to the house porch. She "frenzy barks" so it's hard to get through her mania once shes started. I'll be yelling at her and she wont stop until I've yelled 3-5 times. One beep from this and her ears go down and she comes to the porch very quickly. If she's in a super frenzy, it might take 2 beeps. She is half staffy, half hound so very stubborn barker with a deep, bellowing voice. She has a very slight bay-ish sound. The fact that this collar stops her within 1 beep 95% of the time, is kind of amazing. However, to be accurate of the collar, I will also say that my dog is very well trained. Her only problems are barking and a little nervousness/protectiveness. To give context, she was out with me the other day and some random lady came to our yard. This dog started barking very ferociously as soon as she heard the ladies voice. On one very strong "SIT" from me, her butt was planted and all barking ceased. A very quick response from her but if I had thought to bring the collar remote with me outside, it would have been much faster and less straining on my vocal chords. :P I also use it while out riding my horse. My dog is very good at sticking with me, a little too good as she has gotten almost stepped on many times, but in case we come across another dog, people, or horses, I want her to come to me immediately, plant her butt, and wait without having to yell, just in case the people or dogs or horses aren't friendly. This collar accomplishes that. She can get very protective toward people and too friendly towards dogs but a quick beep from this reminds her to let her mom do the talking. This is great because I can correct her and most people don't hear the beep so it makes my dog look even more well trained than she is! It's also helpful for when cars are going by. I can recall her to the horse and wait for the danger to pass. Range: Our house sits on 2 acres with 1 acre around the house fenced in for the dogs and the other acre for the horses. Both acres are almost perfectly square. With no walls in the way, I can stand on one end of the property and the beep will work *almost* to the other edge of the property(across 2 square acres, just shy of it by about 20 feet. While I'm inside, I can usually beep her successfully if she is barking in the dogs yard. Sometimes, I stand up and go to the nearby window after I've beeped her. She has usually stopped by then and our other dog is still barking so I like to make sure its not her. For some reason, our neighbor only cares about her bark, not the other dog. Battery life: So far, so good. I charge the collar about once a week and it is turned on from about 7am to 7pm everyday. The remote I have only charged once since purchasing it 2 months ago and that wasn't because the battery was low, it was just because my roommate was being nice and charging my stuff for me. Overall, I wish this company offered a cheaper option with just sound correction and longer reach. I've never once had to use the shock on her but I did try the vibrate once. She ignored it completely. I have not yet tried it at the beach with water but I will report back once I have done so. I do think this would be great for many different dogs, if you train them properly with the shock(if necessary) and ween them down to the beep. If it can break through my pit-hound's crazy barking frenzy, it can break through anything(with the right training)!