I really looooved this bag when it first came out - then I tried the GM. Too big. Then I tried the PM. Too small. I waited for the medium-sized one to come out....then, unlike Goldilocks, I did not find it "just right", I just lost interest. I've seen several lately - PMs and the enormous travel size.
Which, BTW, I really do like -- except that I would need a sherpa to go with it.