I also have experience with the Sitka Bivy 45. Must be a newer version than Dreaminof... is talking about, as mine has no metal buckles or stretchy material on the hips. Here is the short version of my review on it.
...My initial concerns about it were 1. Is it big enough? and 2. Are the straps padded enough? The pack really isn't that big but it has all kinds of straps and draw cords that allow you to really expand the volume. Still, I was apprehensive about hauling out meat and gear with it. As it turned out, there ended up being enough room for spotting scope, tripod, a few clothes, stove, camera, wyoming saw, sleeping bag and pad, cookware, etc. PLUS my bucks head and horns, one hind quarter, one shoulder, one side of ribs, the neck meat, and a back strap. Oh ya, I also had my rifle strapped on there too. No way would I be able to fit (let alone carry) all of my buck's meat in one trip. But since my dad was there, he packed the rest of the meat. We made a separate trip back up the mountain for his buck's meat. I didn't weigh my pack but it was well over 100 lbs I'm sure. The straps were pretty comfortable and the pack was really stable... although I did get minor bruising on the back side of my right shoulder. It was inevitable though, regardless of the pack. The stitching held up well under stress, which I also worried about when I first stood up with my heaviest load. There are reinforcement straps that come down from the internal frame to the shoulder strap. They were so tight you could almost make a banjo sound by plucking them. I though for sure they would rip, but the didn't. The hip straps were extremely comfortable and easy to adjust under heavy load to transfer more weight to the shoulders to the hips, then back again when I needed to. On the hip straps there are zippered pockets that are absolutely perfect for carrying small items that you might need right away. That's where I carry my rangefinder, small digital camera, extra shells, and knife. The outside pockets are good for your tripod on one side, and spotting scope on the other. My scope is a full-sized angled scope, and the whole thing doesn't fit completely in the pocket. It didn't really bother me since I keep it in a soft case... but it's still worth noting. Inside the pack there is a nylon adjustable meat shelf which is convenient. You can loosen it to lay on the bottom of the pack, or tighten it to sit about 8" off the bottom. That way you can keep your clothes, gear, etc. in the bottom of the pack without smashing it with meat. There is a large zipper opening at the bottom of the pack to access gear in that bottom section without digging in from the top. Another zippered opening sits on the side of the pack, tight against the internal frame, to access things in the middle. Good planning also went into the top of the pack. The material has a draw string at the top, and another about 12" down (at the top of the frame). That way if you are empty, you can fold the extra top material in and pull the lower cord tight to make the pack lower profile. Also on the top end is a detachable bag that doubles as a "cap" that can be pulled real tight to compress the load. This bag part has 3 zippered compartments and holds a number of items that can be accessed quickly. Even with all these features, the entire pack remains extremely light weight! After putting it to the test, I never once have considered replacing it with anything different. I love it.
