You and your girlfriends should absolutely go Polynesian for your long weekend!
Saratoga Springs, which is lovely, is more of an extended-family resort -- outfitted with condos/villas that have kitchens and washer/dryers, etc. It is better suited to big groups (like extended families or groups of neighbors) who intend to eat/cook a lot of meals "in" and bunk out on fold-out couches, etc.
Our party of 11 just stayed there (Saratoga Springs) last month, and it was lovely, but it's remotely located, if you ask me, and the wait for the shuttle bus to the various parks was long (sometimes 30 minutes). You just can't beat the Polynesian for being a monorail-access hotel (monorail zips you directly from lobby to Magic Kingdom -- no waiting for the shuttle, at least for Magic Kingdom). If we hadn't been traveling with our entire family, I certainly would have preferred the Polynesian.
You can shuttle to Downtown Disney (or drive there in your car), so don't worry about your proximity to it if you choose the Polynesian. If you happen to be placed on the far side of Saratoga Springs (in relation to Downtown Disney) you would be shuttling to it anyway, because it's only close enough to walk if you're in one of the outlying sections (of Saratoga).
You will not regret Polynesian! It's unique, great pool, it has the monorail, and it's pure "Disney." Visit Saratoga when you return on a family trip with all your nieces and nephews and cousins and intend to grocery shop, cook-in and share a bathroom.
Have a great time!