Something to consider when hiking with your dog is the need to carry twice as much water. A couple of years ago we invested in a hydration pack for our dogs for two reasons. The first reason was to have them carry their own water and the second was to help train K’Ehleyr by giving her a job to do and maybe some extra weight to slow her down. Our trainers initially used dive weights in the pack but we learned that it takes more than 10 extra pounds to slow down a rambunctious 100 pound Dane. She also didn’t seem to acquire a sense of responsibility by being given a job but at least someone else was helping to carry the water.
The Ruff Wear hydration pack came with 2, half liter bottles, one for each side. There is also an extra pocket on each side for bags or treats. Construction of the pack is well done but the extra-large just barely fit and by the next summer, after K’Ehleyr finished growing to 120 lbs., the middle strap was about 3 inches too short so now Varel who is 20 lbs. smaller gets to carry the water. The amount of water is not much for 2 Great Danes so we usual hook an extra bottle to it, there is also a handle on the top of the pack to help out when the trail gets too tough.
If you are looking for a dog pack I would suggest reading the reviews and remember you usually get what you pay for. Just like with humans, you want the pack to be comfortable and durable. They also come with a variety of options depending on what your needs are. If you plan on doing all day or longer hikes you might want to look into a multi-purpose pack to carry more than just water.
I can’t compare this to other packs because I only have experience with this one but so far so good, except the size issues.