Before I got into too much detail about this product I must be forthright. I purchased this from Amazon warehouse deals for significantly cheaper than it normally sells - which made this bag an absolutely incredible value! For someone picking this up at its retail price it is still a very solid backpack - however there may be some other things out there closer to price range that out perform this. That said:
Lots of space - 4750 cubic inches is a great space. I was looking for a pack that I can take out for a week (or more if needed) at a time, but that I could also use for a weekend trip. The problem with lots of these bags is that they either sit well below 400 cubic inches, or WAY above. That said, this is pretty versatile and has no problems shrinking down to size. Obviously it can't get bigger than 4750 cubic inches - so that is the limit - which might mean some creative packing (or ultralight trips) for anything over a week.
Lots of pockets - One of my biggest frustrations with current styles of internal frame packs is that they tend to have 1 giant pocket in the main compartment, and then a pocket or two on the outside. Not this pack. It still has the main compartment (which does not have many separate compartments), but has access to the bottom and middle of the pack through the main back pocket as well. This actually makes it kind of like a duffel bag for hiking. If you access through the main back compartment you can access items in the bottom middle or top of your bag with ease. Basically when I get to my tent, I set it on its back, and use that secondary compartment almost exclusively.
Separated day pack - The top compartment on this separates into a day pack - complete with waist band! This is great if you are looking to save space and or weight, but might be base camping somewhere, and therefore might not need to lug around your whole bag and all of your stuff everyday. This pouch is enough for some snacks, a water bottle and some very basic necessities (first aid, sunscreen, map, etc.).
Mesh waist band pockets - This one can not be over-emphasized. This is one of the sweetest parts of this bag, and honestly don't know why more packs don't have this. There are two small mesh pockets on the waist band. This is AWESOME! For me, I pack a small container of sunscreen, my map and lighter (in a Ziploc baggie), multi-tool, and chap-stick. This is extremely handy as these are often things that I need access to while hiking, but don't want to take off my pack.
Straps - Sturdy and very comfortable - however probably nothing that much better than what other packs have.
Ease of Adjust-ability - This bag can be cinched tight horizontally and vertically with easy - and can adjust both the hip strap and the chest strap with ease, even while hiking. The shoulder straps can also be adjusted. This includes how tight the shoulder straps are, as well as their distance from your back. This is handy as I tend to adjust all of these things on occasion while hiking, but want to be able to switch back without hassle.
Bottom of pack access - I already stated that the pack is pretty easily accessible which is true. However my main complaint is that if you pack your sleeping bag inside the bottom of your pack - which most with an internal frame pack do, you are unable to get your sleeping bag out without removing everything. If this is something you're used to no big deal. I still think its a hassle.
Hydration pack compatible - this pack says its hydration compatible - which it is, however that is definitely not its strong suit. I absolutely HATE hydration packs, so it doesn't matter to me, but for those who love them - which is most backpackers - might be something to be aware of.
Size - Ironically I love the size, however when I bought this pack I was unaware that though the cubic inch size is the same for a small and a large pack, the dimensions are actually quite different. I prefer the narrower pack - which is the large size, and that is what fits my body, so it worked out well. Just make sure you know ahead of time.
Adjust-ability - Though overall the pack adjust very smoothly. I have found it difficult to adjust the actual placement of the straps - 17, 18, 19, 20, 21 inches. This isn't a big deal, because once its set you probably won't move it again, however it is a bit frustrating to adjust those few times to get it perfect for your first hike.
I would definitely recommend this pack. For the price I purchased it (sub $100), I don't think there is another pack that could come close to touching it. As stated, there may be other packs in its retail price range that match it, but it is a great pack, I have been very pleased.