XL size was just what I wanted. And very durable construction was an important consideration, since I plan to use this for travel as checked baggage, etc. But, I also wanted a bag that I could use for daily shopping, trips to the laundromat, and so on. So, it had to be both strong AND reasonably light. This bag is so heavy (even when empty), that I immediately took the drastic step of taking a razor knife to cut off extraneous straps and do-dads that were helping to weigh it down. Don't get me wrong...it's a well made backpack, built like a tank. And if you're planning to lug heavy tools or plumbing supplies, or a bag of rocks, this will definitely fit the bill. But, for daily use, this one will likely remain hanging on my hallway hook, providing that gravity doesn't unanchor it from the wall. Not recommended for camping trips or hiking without a mule to carry the load.