I do love the pools at the Poly. It's got a GREAT splash pad for the little ones, and a great feature pool with a fun "volcano" waterslide. The smaller Oasis pool tends to be quiet, and calm with zero entry which is always a plus.
My 4-year-old LOVES the quiet pool - she's frankly a bit of a coward and doesn't like being splashed. My 2-year-old on the other hand is much more gung-ho, and loves charging into the splash pad. She fears nothing and nobody. My wife loves the volcano slide. I love the dole whip!
The only downside is that the Poly is under construction, and the hotel side of the resort remains closed. Most of the shops and restaurants are open, though a few ('Ohana, Trader Sam's) are not. The Monorail stop to Magic Kingdom is closed down, but it's a short walk to the TTC to catch a monorail or ferry, plus they have smaller launches from the resort.
I personally wouldn't let that stop me - I am a (brand new!) DVC owner at the Poly, and have rented there several times in the past, and would love a quiet and less crowded Polynesian getaway.