I have used this pack about 3 times since I bought it and it works great. My dog didnt like it at first but after walking around in it she just forgot about it and would walk and run and try and swim with it. If your dog is in between sizes and is done growing I would recommended going for the smaller size because I went for the bigger size since my dog is almost full grown and it fits everywhere but the front chest strap. I did not have any problems with the pack its self just the water bladder that was in it. After the first hike with my dog one of the bladders started leaking but it was probably caused from my dog or weak plastic. Other than the bladder leaking this is a great pack and I would recommend this to anyone who wants to take their dog on a day hike or a multi day camping trip.