We've only stayed once, and we stayed on the top floor of Bldng 1 with a Disney view. We had no problems with noise at all. The rooms are very well insulated, at least on that side. I did notice that in the early morning, when our room was so quiet I could hear my daughter breathing in the other bed, I could hear a very distant, far off rumble of the freeway--more like a vibration than anything else. But obviously, if it was so quiet I could count DD's breaths, it wasn't bothersome. Going out on the balcony, of course, it was quite a rumble.
I liked where we were for several reasons: 1. the view was wonderful (see page 5 of my trip report, there's a video from the balcony as well, link in my siggy below); 2. we were on the top floor, which meant no little feet pounding above us-- and also we got the lovely skylight; 3. We were close to the street, so when we left in the morning we just came out of the elevator, went out the side door to the left, crossed Manchester right there, and walked down to the light to cross at Harbor and take the shortcut, missing the crowds on the east side of Harbor; 4. We were in the same building as the hotel shop, so if we needed anything we could just run downstairs.