I inevitably returned this pack. Over time I realized it was just not what I wanted. The straps would dig into my shoulders after a while, when fully loaded it would round out like a sausage. I would prefer to carry something that is more streamlined, but has more burly materials. All the straps and buckles on this got on my nerves, especially the thin side compression straps that were a pain in the a** to tighten/loosen, especially when wet.
Weight, durability, and pack space all were far above what I expected to experience when it arrived. It provides an enormous amount of features for an ultralight 46L pack, but spares many common overbuilt functions, which saves weight. The foam frame sheet can be removed for a weight savings of a little over three ounces, but seems to be worth the negligible weight to retain rigidity. It swallowed gear much easier than I expected and does not inherently require an overly skilled bag packer.
I dinged it one star because of the material used on the underside of the should straps, which is a slightly abrasive mesh. If worn improperly fitted it can cause chaffing and make for an unpleasant carry. I tried to remedy this with some duck tape-type wraps to act as a buffer, but decided to give it a try in the natural state first. However, adjustability of the strap and suspension system, plus the stretchy give to the material allows it to be tightened up without being restrictive. Weights of less than 20lbs. can be carried by most quite easily, but ensure proper sizing. For 2012 they came out with S, M, and L, vice the S/M and M/L for previous models. I purchased the M, and imagine someone beyond a 19-19.5" torso would find it a bit short.
It seems to be a formidable ultralight pack for dayhiking and multi-day backpacking pursuits, but I have not been completely swept off my feet with it like I was right away with my larger Granite Gear Blaze AC 60. I will try to post an update once I have a better feel for it.