I couldn't vote!! To hard to decide.
As mentioned, Poly standard rooms have better views, and room size is larger, we had a great room in Tokelau, near beach, and all rooms in that longhouse have balconies.
Great transportation at Poly, with boat or monorail to MK, and has walking path to TTC for Epcot monorail, so only needed bus for DHS & AK.
BC rooms are a bit smaller, but brighter, and fresh. Halls are a lot nicer too.
Poly halls seem dingy.
BC has great pool, walk to Epcot, and can walk or boat to DHS. So again, 2 parks to bus to.
I booked a GV at BC, only $10 or less a night more then standard view, and IMO well worth it.
I enjoyed my stays at both resorts.