I searched high and low for the best daypack for my money and this is where I ended up.
I actually purchased a daypack from Osprey that was absolutely awesome but exchanged it for this one before using it because they were similar enough and I certainly saved money buying the REI one. I love the way that REI can provide the quality and features found in the very high-end products for a more affordable price. I see it again and again with pack, jackets, etc.
I still think Osprey is winning the backpack game right now, but for day hikes, lugging your junk to work, etc. this pack is the best you're going to find (in my opinion, of course).
My only complaint, really, is that there are no lower compression straps (as can be found on Osprey, etc). While the upper compression straps are handy, a set of straps down low near the mesh pockets would really take this pack to 100%. Your gear always tends to "sag" into the lower portion of your pack and, in this pack, it makes the lower portion stick out from your back. A set of lower compression straps would keep things tight and keep the weight just a bit higher up and closer to your body.

I bought this pack to carry my essentials on a three week tour through Australia and Thailand. Granted, you don't need much when traveling in such hot countries, but this pack allowed me to bring all the clothing I needed, a towel, snorkel mask and snorkel, a compressible camp pillow, along with all the other small stuff and souvenirs. The long side zipper pockets worked great for carrying my travel documents and cash because they are mostly hidden yet still accessible enough. Speaking of accessibility, the way this pack's main compartment zips/unzips is super convenient for grabbing just one thing out while keeping everything packed the way you had it. My wife has a top-loading pack of similar size and was always pulling everything out just to get to one thing. The hip pockets and side mesh pockets (bottle holders) were nice for stashing frequently used items. I agree with other reviews that having lower compression straps would increase the load handling ability of this pack, but on other packs I've used this usually means you lose function of the bottle pockets. Lastly, I did feel the empty pack is a bit heavy for the size, but hopefully that means it will last. And the size was perfect for all local and international overhead storage bins--never had to check a bag!

I absolutely love this bag. It sports a sturdy internal frame, and has excellent padding for hips, back and shoulders. I really appreciate the long shoulder straps with padding that extends all the way down to lower ribs and back, which makes it very comfortable.
The clean aestehtics drew my attention right away. I did not need a ridiculous amount of hoops and straps, but it has exactualy what I needed for trekking poles, hydration tubes, and nalgene bottles, or other items I may need.
The bag has a HUGE primary compartment and a very deep hydration bladder pouch to keep them secure. The hydration bladder hook is centered and stitched very well, and will hold up heavier bladders. There are also two bladder tube openings on either side of the pack, so for longer trips, you can double up.
The pack also comes with an emergency whistle that is built into the chest strap, which was a pleasant and useful surprise. I would buy this bag again and again, for myself or as a gift.