I love the Poly and always include at least a few days there on our stays.
The big question for me would be where are the CR rooms located. For me, staying on site is all about being immersed in the theme. At the Poly, the theme is obvious and you pay extra for feeling like you've been transported to a tropical island. At the CR, you pay extra for being in the tower building (which is still pretty cool) and having great views of MK. If I couldn't experience the theme, I wouldn't pay extra to stay on site.
That's why where the CR rooms are located is the big issue for me. If they are in the garden wings, you could be disappointed. You are pretty removed from the Tower and the great views. While I have never stayed in the gardern wings, they seem remote, inconvenient and just like ordinary hotel rooms to me. (I will obviously defer to those who have stayed them.) However, at the Poly, there is no risk that you will not be able to experience the theme. Every longhouse is immersed in it. Some are farther away from the pools or Grand Ceremonial House or monorail than others, but they are all surrounded by lush tropical foliage, torches and Polynesian music. You can't go wrong with the Poly.
Just my thoughts.