i've never seen the GM IRL, but the PM is pretty small...about the same capacity as a pap 26. i think for some reason i was thinking it would be bigger. nevertheless, its an adorable bag! i saw a peppermint one on ebay that was TDF!
The Biscayne Bay was initially my choice for my first Vernis. But luckily the stores here were out of the Perle ones and I went for the Roxbury instead and never looked back!
FYI, the bottom of the Biscayne is vachetta so it is very vulnerable to stains!