 I place this class of outdoor backpacks 3, 1, 4, 2. I place 3 over 1 because 3 has a sternum strap while 1 does not, and 3 has a rain cover attachment while 1 does not. Grant, 1 is made of ripstop nylon. I place 1 over 4 because 1 is a weekend pack with a capacity of 40 liters, while 4 is a multi-day pack with a capacity of 55 liters. Grant, 4 has a sternum strap. I place 4 over 2 because 4 is made of ripstop nylon while 2 is made of cordura nylon. Grant, 2 comes with a rain cover attachment. I place 2 last because it is not a weekend pack and it is not made of ripstop nylon. For these reasons, I place this class of outdoor backpacks 3, 1, 4, 2.