The Ariel 65 is easily the best pack I've used. I tried several different backpacks that were fine but not quite right - but from the minute I put this one on I knew it would go on many adventures with me. From one-night trips to two-week treks, this is the only pack you need. Great fit, great features, and durable.
Let's start with the fit. I'm 5'0" and 110lbs and got the XS. This pack is so adjustable that you really can make it fit perfectly - especially since the waist belt is heat-moldable to fit you exactly right. Once it's on and adjusted properly, I don't find myself having to fiddle with the straps during long days on the trail. If you pack it correctly it also balances really well and I never worry about wearing it for stream crossings, light scrambling or sketchy footing.
Now on to features. I love the stretchy front pocket for maps, an extra layer and/or a snack. Easily accessible and you can cram a lot in there! The brain is also well designed and very easy to convert into a lumbar pack - on day hikes from a base camp I've been able to fit a 1L water bottle, down jacket, camera, map and snacks just in the brain! The trekking pole loops are a nice feature, as is the sleeping bag compartment - you can attach it to make separate compartments in your pack or detach it depending on your preference. The mesh panel on the back vents well.
Finally, it's durable. And backed by Osprey's bomber warranty, you never have to worry about pushing this pack to the limit and treating it a bit rough.
I'm not the biggest or strongest person out there, but this pack lets me fake it a bit - I've stuffed it to the limit with 60lbs of gear and it was STILL comfortable! I highly recommend this pack to any ladies who want a great fitting, all-around awesome pack.