I bought the small bag because the large bag was too heavy and expensive for my taste. I carry my wallet and some small items in the front pocket and a SLR in the main compartment, sometimes with an extra 50mm lens. My daily food is in the front-left panniers and jacket in a small backpack on top of the rear rack, all easily accessible. I carry lots of photo equipment sometimes and need a small photo backpack for dayhikes so I'm thinking of leaving the bar bag altogether and put the photo bag on a front rack with platform.