I've had this pack for a few months now and I like it a lot but I'm disappointed in a few aspects of it. This pack will keep you cool in the summer for sure, but I found it a bit uncomfortable, even after trying a variety of different ways of fitting it. It creates pressure points on my upper and lower back where the padding is (not enough padding) that start to get sore after a while. It's also not as durable as other packs I've used. Some of the stitching seems to be coming loose, especially in the roll-top cover part where the fabric gets bent around a lot. Another thing to be aware of is the fact that there are two pockets (one on the side, one on the front) that have external access, but aren't actually external - they take up space inside the main compartment. So think of how it feels when you have tons of stuff in your jeans pocket - it just creates a ton of bulk.

Overall I can't be too disappointed, I got this bag at a heavy discount. For ultra-light summer backpackers who don't want to sacrifice features, this is well worth it. I just wish I went with something that was a pound heavier in exchange for better padding and durability.

Extra features in packs often rings like a red flashing light on the interior of a submarine- never a good thing. At least in the minds of a minimalist and seasoned backpacker. Mountain Hardwear has made these extra features be totally functional and taken the 'bells and whistles' idiosyncrasy out of them. What are these features? Well starting with the daisy chain- these often can clutter not only the appearance of your pack but typically manufacturers will make them much longer than needed, contributing to overall weight and unsightliness in one fell swoop. So the daisy chain is all you need, nothing you don't. The roll top design which is also sealed by magnetic closure, is functional in the sense it eliminates the removable top construction we still see today in so many packs. If you're like me you find satisfaction in taking those off before your excursion, Mountain Hardwear knew we did this and had no desire to use it as a lumbar pack, so they cut it out altogether. The mesh hipbelt pockets are used for my camera on one side and a compass on the other for quick access. The stowable front pocket with compression strap is unlike anything I've ever seen on a pack. It's so convenient on those days when you don't know what layer you're going to be pairing up with or for stuffing a rain shell in for quick access if it looks like rain might be in your near future. I suppose it could even hold a helmet if you were canyoneering. There is compression all over the place so leaving with an empty bag doesn't mean you're leaving with a floppy, ill fitting bag. The mesh back and arched framesheet keep your back cool and core temp down. The Koa to me represents Mountain Hardwear's future in the pack industry, If such a thing as a "blind pack test" existed, most of the results would say they were wearing an Osprey Atmos when asked what they thought of the Koa.

As far as sizing goes, I'm 6'1" and I got a medium and it fit absolutely perfect (I'm more legs than torso -about a 21" torso). I wear a large in Arc'teryx and North Face packs, but this medium was spot on.

My only complaints are I wish ONE of the hip belt pockets wasn't mesh so dirt and sand couldn't get into it in order to keep a camera cleaner. I also wish the drink holders on the side were deeper- that's it.