I've tried both the PM and the MM. They are clearly meant to be handheld. I can fit both on the shoulder, but the straps are a little short for this purpose. I don't think it'll be comfortable carried that way for long, especially the MM, which has a really wide base and your arms will stick out away from your body a bit akwardly, and the bag's a little too big to "swing" backwards completly, KWIM?