That may depend on your definition of best. We've stayed at the GF, but not Concierge Level (not sure I'll ever be able to afford that). From what I remember the types of drinks and food available at the Polynesian and the CR are basically the same.
The last time we were in the CR lounge it was nice. It's roomy and you can watch Wishes from the balcony. However if you have a park view, you can watch it from your room. The nice part was being able to go from your room to the lounge and back without going outside.
At the Polynesian, we were in a different long house than the lounge and had to walk outside, sometimes in the rain to get there.