The main large pouch is HUGE. And, because it opens up completely, it's easy to pack clothing in an organized, and easily-accessible, fashion. I was thankful for the straight jacket straps, so I could stuff it full of clothes and still fit it under the plane seat in front of me (barely). However, those same straps that are so handy, also make it difficult to access any of the pouches, including the vertical zipper that would have been so handy for travel documents. Instead, I places ID, passport, wallet etc. in the small pouch on top (I think it's meant for ski goggles?). I liked the easy-access laptop pouch. It was also a good place to keep souvenir photos from being damaged on flight home, as there is a second zipper pouch within the laptop pouch. If it weren't for having snorkel gear and 3 different sets of footwear, I could easily pack a week of clothing and travel gear in here!
My husband and I like to travel on a budget and with minimal things. With the airlines charging for bags now we decided to get this backpack as our personal item. We flew basic economy to Florida for 5 days on united. Basic economy now means you are not allowed a carry on or checked bag without a fee. These bags fit perfectly in the measurement station. Granted we didn't have any room for our feet... we were just happy to have all our things with us. When we measured our bags they were actually 2 inches longer and wider than the measurements online. So we were super pleased to get through every check point with no troubles.