This is funny, because my last trip was a split stay, and I stayed Poly Garden view, then went to AKL club! I only went to AKL because I wanted to do the Sunrise Safari, but I was surprised at how much I liked the resort.
I don't find Club level to be worth the extra money. The lounge wasn't located on the same floor, so it wasn't convenient. We hung out there when waiting for our room, and didn't go back, except to meet up for the safari. I just don't get what's so great about club level.

If you are interested in the safari, go for it, but otherwise, save your money and buy your own snacks.
The Poly is a much smaller resort, and as I trudged the extensive hallways at AKL, I found myself missing the intimacy of the Poly. The Poly also has a location advantage. Many dining options are just a monorail hop away at the GF and CR. The AKL is rather isolated.
So, I chose Poly. But I really don't think you can go wrong with either choice.