I've had this pack for over a year, and I can certainly say it has a lot going for it. I've found this pack accommodating to a wide variety of uses, be it for traveling, backpacking, or simply having it ready to go for a bug-out scenario. If your intention for this pack is backpacking, most people out there would suggest that the Redwing 3100 is suited to short excursions of about 2-3 days. Though, if you are someone who is capable of some level of self-reliance and bushcraft, and pack with an extended/long-term stay in mind, this pack can very readily provide for your needs. There are a lot of great things I could talk about here...
The construction is very solid, though anyone who is familiar with Kelty knows they make an awesome pack. You'll likely be buried with it. Mostly durable nylon, with straps that make adjustment a breeze. It's got a sternum strap, and a hip strap that makes for a comfortable and evenly-distributed load.
Amongst some of the other features of its construction, the internal frame is adjustable and makes carrying a heavy load pretty easy. Generally speaking I load it up to around 50-60 lbs, which I find to be adequate in carrying the necessities. The main storage is very roomy and open, simple and effective. Within the main storage, there's also a sleeve for a hydration bladder as well as an output from the top. There's a lot of great pockets that have multiple functions. The outside storage is fantastic, it's the perfect size and is organized cleverly for all things that need to be readily accessible. The compression straps along the top make carrying external items pretty simple, and there are also two rows of strong daisy chains along the bottom for the same purpose. Speaking of daisy chains, loops, and things of that nature, the pack has them all over the place, which are not a main selling point, but they round the pack out nicely. From the various loops you can stow things like an ice axe, survival shovel, (Cold Steel makes an awesome multipurpose one that I highly recommend) trekking poles, you name it. With some clever attachment you could probably add a smaller bag, as well. One of my favorite features about the storage on this bag are the side pockets, which have two compartments. There's a zippered compartment, which is sized to maybe a 1.5-2L bottle, but between the pocket and the bag is another, flow-through pocket. The bottom of it is closed with velcro, but in undoing the velcro you can slide something long and otherwise unwieldy down through it, such as a rifle or trekking poles for example. The netted pockets beneath them are aligned perfectly to catch whatever you slide down through their, such as the butt of said rifle.
Some people may harbor some criticism as some people prefer top-loading style packs, or packs with multiple points of entry into the main storage. I don't really share this preference. There is plenty of outside storage to keep the main storage purposed for things that only get taken out periodically or at camp.
I got this pack on another website for $70, and if you hunt around I'm sure you'll be able to find a similar deal. This is a steal, especially when compared to other packs of comparable function, like an Osprey. I'm not talking smack on Osprey, they make *amazing* packs, but some people who pack efficiently and to necessity don't need to shell out the money they're asking for their packs, though they may be worth it in the comfort they provide for long-term hikes. This is an incredibly versatile and functional pack but I would say it is mostly relegated to multiple day trips.. It's a bit too much for a day hike. When I go backpacking/traveling for example, I typically take my REI Flash 18 with me also which converts from stuff sack (which I keep my sleeping bag in) to light-weight day pack for forays from camp/dwelling/etc.
Overall, for the price and function, you can't beat this pack. I'd give it ten stars if I could.