Bought this backpack for a month long tour of Europe. Went through 6 countries, many train, bus, and airplane rides and it performed amazingly!! Full size zip is crutial for accessing your stuff without needing to repack everything. Plus, lots of expandable room in the front pouch and other pockets for easy access to stuff. I was able to use it as a carry on for all airplane trips so no extra fees. Very comfortable, with multiple ways to adjust the fit so you can get it perfect.