These soft packs also offer little or no protection against impact or crushing damage, but are easier to pack tightly with survival gear. Better quality ones are water resistant and the dry bags are waterproof. Lesser quality packs generally won't keep the contents dry. All but the dry bags should be treated with Scotchgard or similar treatments to help keep contents as dry as possible. You can also put the contents of the kit into plastic bags for additional protection.
Backpacks obviously lend themselves to wilderness travel.
You could make arguments for either type of container. I chose the soft pack route for normal use since this was affordable for me and allows me to cram more into less space. I use red Cordura nylon backpacks. Suck It Up Another thing to consider is vacuum packing the equipment and supplies inside flexible plastic film or bags. The advantages are worthwhile, though vary depending on what sort of case or container you use.