I believe the AKL is the best for overall concierge service, BC comes in second and their food is amazing, then finally Polynesian. I placed the Polynesian last because in my experience, it's premises is the most run down and overall service, including maid service fluctuates like the wind changes direction.
When we stayed in December last year, they brought us up to our room which was allegedly clean. The room looked like it had been hit by a hurricane. We were compelled to clean it again ourselves even after maid service.
While the Concierge planning desk and the Concierge offerings were wonderful, the other aspects of the experience were sub standard when conpared to the overall Concierge experience at BC and AKL.
One of the major aspects that keeps us returning to the Polynesian is the monorail, the view of the Castle, the fireworks and light parade at night. We prefer the third floor and the view is amazing.
Still, when we stayed last in room 3509, there was a marble tile in the bathroom that had been subjected to so much "questionable substances" directly in front of the toilet, you felt compelled to step around it anytime you walked in.
This is not an experience I'd recommend shelling out the $330-450 a night it costs to stay there.
Put a monorail to AKL and you won't be able to stay there unless you plan months in advance. BC is just wonderful in itself. Totally different experience. They served dishes such as "Lobster Turnovers" and "Chicken Wellington" along with an abundance of Chocolates and other goodies.
Decide on the type of theme you really desire and let that guide you. If you also want to be close to the park, there's no better choice than the Polynesian in my opinion, faults and all.