I bought the Ruffwear Singletrak Backpack for my 70 lb. Rough Collie. I wanted a lightweight, low-profile backpack with good ventilation that could stand up to a variety of sub-optimal terrains and rough treatment. Atticus (my dog) and I enjoy hitting the trails, marshes, fields, and beaches that come with living on the South Carolina coast, but we also needed something he could wear around town without looking silly in. I bought the Medium size in Cloudburst Gray to go with my dogs 29" girth. After using this backpack for a few weeks in all kinds of terrain I have to say that this pack is pretty close to perfect. I've owned several other packs from a Kurgo Baxter Pack to a Outward Hound DayPak, and this pack is by far the best made pack we've ever owned. It's made out of quality, durable materials with careful detail to the seams. The zippers are seamless and don't catch. I was skeptical over if I'd actually be able to lift my 70 lb. dog off the ground, I DID!! Not only that, but he didn't even seem all that uncomfortable with it. A lot of packs push the 'handle' feature, but until now I've never actually owned a pack that would let me lift my dog without risking the packs integrity. It's no belay harness, but it will certainly do for extracting a dog up to his ears in pluffmud. I was a little weary of the plastic clip instead of the metal D-Rings I'm used to, but it has held up just fine. My dog is fairly well behaved on a leash though. I may not trust it to hold up against a heavy puller though, if your dog is I strongly recommend clipping into a backup system (like a slip collar) in case the ring does fail. The pockets are a perfect size for the water bladders that come with it, I fill mine halfway then freeze the water so it helps keep my dog cool in the blazing heat and humidity. In the other pockets I usually put a snack for me, and a snack for him. I have a small collapsible bowl that I snug in behind one of the water bladders, however if you have a fabric collapsible bowl you should be able to fit it into the side pockets just fine, and if all else fails you can always clip a bowl to the D-Ring or leash with a carabiner. The pockets without the water bladders are actually quite roomy and can easily fit one of his tug toys, my tablet, my keys and wallet, and several other items in them. What I really love about this pack though is that it doesn't hinder my dogs range of motion. It's slim design allows my boy to do all the things he does without it, and that is just awesome. He doesn't overheat despite the 105 degree heat index because of the the great ventilation, and I know that I can rely on this pack to hold up to all sorts of adverse conditions. I've fallen in love with this pack, and my dog has too! Every time he seems me take it out his tail starts wagging, and he knows we're in for an adventure! To Summarize: Pros: Great ventilation to prevent overheating Usable Handle for lifting, supporting, and extracting (even large breeds) Great quality materials and build Low-Profile does not impede movement No Chaffing Highly Customizable ensures perfect fit Super durable and easily cared for Cons: May need to use a backup (such as a slip collar) when utilizing the non-metal D-ring for heavy pullers. Have to lift dogs front leg to slip into harness