I've always avoided Arkel handlebar bags because they are heavy and over engineered. That was true of their panniers too unt they brought out te Drylites which look interesting.

Anyway back to handlebar bags. I've had a few and eventually settled on the Ortliebs Classic. It isn't perfect as te lid snaps are a bit of a pain, as us attatching the shoulder strap and the Ortlieb mount is best replaced with the clamp on Klick Fix mount. But the Ortlieb us simple, relatively light, waterproof and easy to take off the bike when you lock it up and leave it somewhere. I like the single large compartment as I can fit my valuables wash kit, electronics and most of my food in it.