Carrying them can be awkward. The handle to remove them from the bike is not really built for carrying them, if you need a better handle clip the 2 ends together to make a better handle. The shoulder strap works well, but can be a strain for heavy loads or long amounts of time with it. The Ortlieb Carrying System(backpack mount) is great. I uses it ever day, it's just like a back pack then.

Ortlieb does offer a kind of added pocket for the outside, you have to mounted on the back your self. And it big and awkward(Outer Pocket Large) I think I have seen a mess pocket that mounts on the outside to, but I cant find it right now.

I got mine from REI during a sale, maybe around $120.