the ortliebs are semi-rigid in construction by virtue of the hardshell frame, bottom sheet that wraps the sides, and backplate. A little foam/plastic cut to size for front and top if you're concerned about it, add the divider insert, and you've got a great handlebar bag for shooting on the fly.

The bags' design lets you access them easily while riding.

I can't see any reason to go with anything besides the Ortlieb.