If you love noise, both inside and out, stay here!
Although our room was clean and nicely done, I would have sworn the window was open when we arrived. There is NO insulation and all sounds can be heard from the street. I stay in major cities frequently and this was one of the worst rooms for noise, ever. We could hear the "El" (metro train) all day and night, people speaking, dump trucks, sirens -- everything. AND from inside the room, you could hear your neighbors hang up their clothes in the closet, shower, shave and dress as though they were sharing a room. And, on the last night, having the pleasure of being above a ballroom, we could hear music from below until after midnight. I thought we just had a bad room, but others in our group (over 20 people) said they also found it a VERY NOISY hotel. Apparently, the W spent too much money on the lobby and not enough on the insulation. I would recommend staying elsewhere. The Marriott across the street was nice the last time we were there. And as both are close to public transit, the Art Museum and the Loop (if you're there for business), I'd recommend elsewhere.