We faced the same decision when we bought and we went with BW. We have three kids (now 6,7,7). We loved the idea that when they were little and needed to be in bed early, we could put them to sleep and still sit on our BW view patio and watch the "action." I felt that once the kids were in bed at WL, we still had the balcony, but really had nothing to entertain us. I also love waking up to the quiet lake in the morning and honestly, the noise has never been an issue unless we've forgotten and left the balcony door open a crack.
We still love it to run to EPCOT just for fireworks or to get something quick to eat and the kids love walking around the lake at night, playing in the sand, and interacting with the street performers. We have a wide variety of resturant choices as well (@ BW, Swan, Dolphin, BC and EPCOT). Love it, love it, love it! When the kids get a bit older, they will also be able to have a little freedom to explore the boardwalk and EPCOT, while not having to navigate transportation.
Could also be that I'm from Minnesota and WL seemed too dark for me on vacation! I wanted sun and bright rooms!