I use this for a 4kg rescue cat. I think it’s overpriced, but it also seems to be the only pack of its kind on the market, so for me it’s worth it. Mostly I really like it, although when I use it I'm often finding ways it could be improved, and I’d buy an improved version. The good: Function - I travel regularly between two cities with my cat, a 90-minute commute that requires biking, walking, and several buses. Although I travel light, I generally need to bring a laptop and a few other items. This bag is perfect for that, and also inconspicuous and looks like a normal backpack. Pets are allowed on the bus, but my cat prefers not to have a lot of human attention, so he likes that he can see out the side vents, but people don’t notice him. The laptop compartment is roomy, although it won’t fit too much more than a laptop before it starts to intrude into the pet compartment. The pack is well-ventilated (at least for a cooler climate), and still keeps the cat dry in a light drizzle. It has a convenient number of pockets. I’m a smaller woman (47 kg, 162 cm) and had to adjust some of the straps to the shortest settings, but it’s not uncomfortable and I can wear it on my front as well. Cat rating - Cat is obsessed! I have to hide this to keep him from constantly trying to claw his way in, so instead he finds other backpacks in the house to curl up on. Granted, my cat was already excited about his carrier, and he likes to snuggle under covers and is not claustrophobic. Mileage may vary with other cats. I use additional padding in the bottom for longer trips. He can lie down, but there's not a ton of space left over, especially if I'm packing other stuff. Durability - I’ve had the bag a few months and it seems to be holding up well, even with abuse from the cat, who protests not being in the bag by trying to shred holes in it. As a result there are some minor perforations and runs in the fabric/straps, but it’s only cosmetic. The not-so good: Support - The hip straps really aren’t great. The pack doesn’t have a fully padded or detachable hip strap like the typical hiking pack, despite this pack being in a similar price range. Because the hip straps don’t actually fully encircle the hips, only the sides and the front, and the pack has no internal framing, the backpack tends to slide down in the back and hang off the shoulders, even with the hip straps fully tightened. If my pet were much heavier, this could be really uncomfortable. Security - I feel like this doesn’t offer much protection from bumps or from falls to the side, although for a more solidly-built animal than my little cat, perhaps this isn’t such a concern. The outward-facing part of the bag is soft and collapsible, and so the inner area is kept open during use by the weight of the cat in the hard base pulling the bag moderately taut against my shoulders. On the bus I’m always worried about people elbowing or pushing against my cat, and a bike accident could be catastrophic. The optional support bars add very little structure, aside from preventing the bag from completely folding in half. A better design (for cats or small dogs, anyway) might include plastic sheeting or boning inserted in the outer panel, top, and sides of the backpack, to give some reinforcement. I also don’t think the fabric is waterproof, and perhaps it should be at this price point. Price - I feel like it's good quality construction, but for a similar price you can get high-tech hiking backpacks with super light frames, waterproof fabrics, etc., while this is just a regular backpack with some extra padding and clever design elements. I feel they're able to price it like this because for whatever reason, most pet backpacks lack space for human storage.
