Here's my rankings:
Pool:
1. Poly
2. CR/AK: CR pool isn't super exciting, but quiet pool is very tranquil. sometimes get it to ourselves.
AK pool- has benefit of being sheltered by hotel. Big bonus if traveling at cooler times of year.
3. CSR/POR
4. BWK
MK Convenience:
1. CR
2. Poly
3. BWK (not close to MK; but easy walk to Epcot/HS)
4. AK/POR
5. CSR - POR transportation really ranks overall with CSR, but it just happens to be located close to MK.)
Theming:
1. Poly/AK
2. CSR/BWK
3. POR/CR - theming isn't exciting at CR, but in general, it is rather relaxing, and the tower views are super. We actually prefer non-theme park view, as that side has pretty lake +balconies get morning sun/afternoon shade. Never stayed non-tower.
DINING:
1. Poly
2. AK/CSR - VERY curious to try NEW dining at CSR
3. BWK/POR/CR
Hotel LAYOUT/EASE of GETTING AROUND HOTEL:
1. CR/AK
2. Poly/BWK
3. POR/CSR
WHERE we tend to STAY:
1. CR
2. AK
3. CSR
4. Poly/BWK
5. POR
Though I don't find the theming of CR super exciting (Poly is much more fun vibe/pool/dining), at the end of the day, I love the layout, location, and relaxing nature of CR. Partly it was room location, but Poly rooms are brown/dark, and I just didn't like the room layout. AK rooms are also quite brown, but there you get a fun vibe and animals. BWK/CR/CSR have brighter, lighter rooms. POR is kind of in-between. POR/CSR/BWK are kind of big and sprawling. You can spend a good deal of time just trying to get from your room to food court or the pool. I DO like the BWK and Poly as places to visit and dine! Both have good options if you don't have specific ADR's.
I am interested in seeing the new tower of CSR!
We also often do split stays ourselves! If you can't quite decide. Sometimes we do an even split, other time we do just one night...depends a little on the kind of offer/availability. Otherwise, consider visiting all of them, maybe try the dining at each if you haven't before.