Carrying comfort should be your first priority in a pack. After that, it's the little things that improve versatility and ease of use. To decide which pack is right for you, consider the features below and the type of hiking you do.
Floating lid. A lid that "floats" on extendable straps can cover overstuffed packbags without banging your head, and buckle over climbing ropes, pads, or tents.
Quick-release compression straps. Compression straps on each side of the pack hold fast to skis, tent poles, and sleeping pads. They also
make the pack more stable when it's lightly loaded.
Lash points. Double lash points (so that both ends of a lashed item can be secured) add tremendously to load-carrying capacity. You'll need to supply the cord, elastic, or webbing.
Ice-axe loops. These webbing loops are nearly essential for carrying ice axes, whether you're a climber or a mountain hiker. They're also handy for carrying collapsed trekking poles.
Water-bottle or wand pockets. These pockets keep water within easy reach and tent poles outside the pack, where they're less likely to get bent.
Elastic cords. A lattice of bungee cords across the back of the pack is an easy way to store wet rainwear, crampons, and other items.
Shovel (or shove-it) pocket. This is a convenient storage spot for an avalanche shovel, raingear, and other gear you want to keep handy.
Outside pockets. These allow organizing options and the ability to store fuel outside the main compartment, but they do add weight and bulk.
Extension collar. This tube under the lid extends the length of the main compartment, enabling you to pack even more, for better or worse.