We just got back from our first Poly stay and it was amazing!
We'd requested Fiji 3rd floor and wound up with Fiji 1st floor, which I was perfectly fine with. We primarily wanted to be away from construction and have either a patio or balcony we could enjoy when the kids were asleep, so this fit the bill. We were in 1310 - Luau side, you could enjoy the music from the patio but it wasn't overly noisy from inside the room - perfect. We loved being able to walk right off the patio to the beach and watching the duck family swim around in the rain puddles right outside our room (and not having to deal with the elevator in our building was nice with the strollers).
We ate at Kona several times (2 breakfasts, 1 lunch, and a take-out dinner) - food was always very good, but service was nothing to write home about. One of the servers seemed like what we'd consider a good server around home (but still not "disney great"), and the others were just okay. For the take-out, they told me did take out, but then it took several minutes for them to talk to us/take our orders (there was another person doing the same thing). The service here was kind of a bummer (DH mentioned it too, and I think he's more lenient than me), possibly an anomaly but it seems like there is room for improvement. We do really like the food though (obviously)
We did Ohana dinner at Ohana (I tried to convince DH to do the in-room, but he wanted to do the restaurant). It was very good and our server here was friendly and attentive

. Our girls (almost-2 and 4) enjoyed it, the 4-year old did coconut races and I appreciated that they put big kids in front so the younger ones could go at their own pace/with parents nearby.
Captain Cooks - we never had a very long wait and food was always good. The girls got a kick out of the CM at the entry waving with the Stitch hand
We only made it to the pool one evening, but didn't find it ovecrowded and also enjoyed the campfire/movie and Wishes from the beach (really a nice vantage point and music was piped in).
Overall great stay and I would be delighted to stay here again!