I've stayed at the WL and the Polynesian. (I have pictures from both resorts on my web site, the link is below in my signature). We loved both resorts, however the Polynesian is definitely #1, in our opinion. This is because of the location, overall theme, restaurants, and transportation options. You have the monorail and the boats to take you back and forth to the Magic Kingdom, but you're also a short walk to the TTC where you get the Epcot Monorail too.
I love the volcano pool at the Polynesian; no where else can you swim at night and watch the fireworks over the castle at the same time.
On the other hand, DH and I really enjoyed sitting in the large comfortable leather chairs in the lobby of the WL at night after a long day, and just relaxing...people watching...listening to the sounds of the bubbling brook... Like I said, we really did love both resorts, but the Polynesian is our absolute favorite
The rooms at the Polynesian are large, some of the largest on Disney property, every room has 2 queen beds and a day bed. This was perfect for us since we have 2 teen boys who like to have their own beds.
When we stayed at the WL we had a room with a queen bed and a set of bunk beds. The bunks were OK, but for our boys' ages, the headroom was very, very tight. Especially on the bottom bunk. An older child, or an adult, can't sit up in bed on the bottom bunk, there's just not enough room between the bottom and top bunks. I don't think we'd stay there again in just 1 room with our DSs again. We'd either have to get a deluxe room with a day bed, or two regular rooms.
As far as noise level goes, we didn't hear any noise from either resort.