Either you are buying camera backpacks or camera sling bags, you should choose one that is durable & of top quality. It is imperative that the bags can carry your camera equipment with ease & protection. Bags that are high priced usually come with warranties. You should ask about the warranty for the camera bag especially for the high priced types.
Many colors & designs for your camera bag are available. The ones which are built to withstand harsh weather conditions cost more than the typical ones. You may also opt for the camera bags which have rain covers to protect your camera equipment from becoming wet. Also, the extra compartments for other things could come in handy too. It is safer for your precious camera to be in a camera bag when you are traveling than on its own.