Osprey is the indisputable king of backpacks, as you will find if you conduct hours of research before asking my brother to gift it to me for my birthday. So with the brand down, for my particular needs (moving my entire livelihood in a bag) the 70L is the model to go for. I love the detachable day pack which is effectively my daily gym bag and also my short trip bag. Took to all sorts of climates, adventures in nature and around the world. Still as good as new. It's phenomenal