AKSAR has summed it up best in regards to military vs recreation hiking backpacks

Over the years, I have found through trial and error (and a lot of money) that there is no one perfect backpack and at one time, I had over 20 different packs. The pack I use for multi day hiking in the summer is not good for winter. The pack for day hikes does work for a fishing pack, the pack used for EDC for work essentials does not work for day hikes and so on.

The best advise for anyone is - don't cheap out any pack and stay away from the poorly made knockoffs and purchase from a reliable store such as REI or in Canada at MEC. A well made pack will last you a lifetime - and probably more. When purchasing your pack, don't buy it because the color is cool etc. Instead, proper fit is essential and most outdoor retailers will have various types of padded weights and general camping items to add to the pack when you are testing. Also ask if the pack is available in a short, standard or long lengths. It is surprising how an ill fitting pack can be if the length of it for your body frame is too short or too long - even by a couple of inches.