I'm a puppy user also, and I think both mint and puppy/puplets was great OS.
everyone is different, so it's a matter of personal preferences to choose a DE.
if it comes to GNOME vs. JWM, I think it's about a habit, as a former MS windows user, I realize that gnome was offering the (kind of) same feeling of MS windows desktop. JWM was light, but Gnome was offering more functionality on it's heaviness. Same goes to KDE and XFCE, heavier the DE, usually its offering more function. back again, its a matter of personal preferences.
ASUS 1215B AMD E-350 with Linux Mint 15 KDE, Precise Puppy, and Saluki