I love love love the Poly!
The rooms themselves are great. Roomy, well-decorated, with split bathrooms. I only have two little ones, but always felt like we had plenty of place to stretch out, even with the double stroller and inevitable popcorn buckets.
If you're looking for studio availability, that doesn't tend to be a problem at the 11-month window. I know a few resorts (*cough* CCV *cough*) have issues on that front. But while the Bungalows are point-hogs for sure, but most of the rooms are Studios and from what I've seen so far 11-month availability is good. Obviously nothing is guaranteed, but I'd say it's an advantage over the other resorts with similar expirations.
Location is wonderful -- easy access to MK and Epcot (via TTC monorail) to get there first thing in the morning, or to take a quick mid-day break back at your resort.
And if you're NOT an all-day theme park commando, there's no better resort at which to relax. Grab a dole whip, and sit out by the Ceremonial Lawn, or down by the beach, and listen to that Polynesian music just take all of your stress away. (My wife and I were just reminiscing about our last trip in January, and the memory of our little girls playing in the sand, with the music in the background and the Castle visible in the distance, was perhaps our happiest memory. Absolute peaceful bliss.)
The pools are great. The Lava Pool is a ton of fun, with a great kids' splash area, and the Oasis Pool is calm and relaxing. Zero-entry is awesome for little ones!
I know that a lot of the resorts do activities -- even if they're just pool parties -- but I think PVB is top-notch along with AKV. Plus, most of them are on the Ceremonial Lawn, so it's easy to watch little ones from the comfort of a table... and a dole whip... or those thai meatballs from Captain Cook's...
Speaking of food, the options are great! Captain Cook's is seriously one of my favorite QS on property (pro tip: you can get Tonga Toast for breakfast for waaayyy cheaper than at Kona Cafe), and the dole whips are a must-have. But Kona Cafe and 'Ohana are also crowd favorites, and Trader Sam's Grog Grotto is an absolute must-see if you're at all interested in adult beverages, and maybe even if you're not. (Even pro-er tip: watch 20,000 Leagues Under The Sea before you go, and be on the lookout for Ned Land's homemade guitar!)