Winter hydration heaven.
I've tried several winter backpacks with built-in hydration systems. When it gets cold enough, they *all* freeze. However, my Stash BC is, by a mile, the best: it's only frozen once, when temperatures were around zero Fahrenheit. Having the drinking tube zip into the strap makes all the difference. The downside is that it takes a little longer to extract the tube; the upside is that the tube doesn't flap around, and, most importantly, you can actually drink liquid! Apart from that, it's a great ski pack. Size is about perfect for a one-day backcountry outing: takes shovel, probe, food, spare clothing, radio. Looks great (particularly the red version), light, comfortable, well-made. Has adjustable ice-axe loops, plenty of attachment points, reinforced ski straps (takes skis vertically, diagonally, A-frame), waterproof zippers. I've yet to find anything about this pack that I don't like. A+.