CBR is a nice moderate resort with a nice playful atmosphere , the rooms are nice and simple and the grounds are well kept. There is bus transportation to the parks and you are really close to EPCOT and Hollywood studios, so fireworks can be viewed from the pool area. There is no scheduled renovation at this time for CBR. When I stayed there many years ago, I enjoyed it.
The Polynesian has several pros in regards to transportation. It is on the monorail line and you can actually walk over to the ticket and transportation center and catch a separate monorail over to MK or catch a connection to EPCOT right there.
They have remodeled the main pool and it is stunning!
****Something to keep in mind though is that they are still working on renovations and will be until Spring of 2016. Room rates will not change much but you will have the added ambiance of cranes, bulldozers and folks working behind big green walls.

We stayed there this past January and the main pool was closed at the time. but we got to see the new bungalows being worked on from our room.

And we got to see the pool being worked on too. We were given free passes to Typhoon Lagoon and Blizzard Beach because of the work being done on the main pool.
Right now they are working on the smaller pool and will be until early Spring 2016.
You can sit on the beach at the Poly and watch the boat parade and fireworks with piped in music. This was a definite bonus for our family.
Whatever you decide, you will have a wonderful stay and enjoy some great Florida weather. It is a bit chilly here then, but there is no snow and that is a bonus. lol
Tracey