When I read a bag review I always look firstly at whether it has a rainproof cover (as opposed to a 'treatment' or even that dubious statement from less salubrious sources stating it is waterproof - lol). As a photographer that firstly lives in the UK (it rains a lot), often on Dartmoor (it rains even more) and near the coast (rain and salt spray) protecting my gear is paramount. How easy it is to apply and remove that rain-cover also factors in. Secondly I look at internal dimensions (will it accept a 500mm? mounted to camera body or not?). There does seem to be a city dwelling often mirror-less crowd who like the man-bag style. Ideal for those who travel light or are travelling and dashing between underground stations ? They suit the smaller kits. In the wilds though life and weather is tough and your bag needs to be as well. They are cheap compared to repairs.