Great Location, Really Loud
Most visits to Seattle I have stayed with family, or out on Bainbridge Island, so this was my first time in a downtown hotel for business. The Grand Hyatt had a great location, easy walking distance to shops, restaurants, and my meetings. It's diagonally across the street from Pacific Place (high-end mall), about two blocks from the flagship Nordstrom, and maybe 10 minutes to Pike Place. 
My deluxe king room had a nice layout, huge bathroom, and very cool automatic blinds. The room itself, though, had no convenient power outlets for charging electronics or using a laptop. I wound up charging my phone in the bathroom and putting my iPad on the floor. 
My room was on a lower floor, and the windows were not the most soundproof. Traffic noise did not really bother me, but there was a steady, loud hum (perhaps from the air conditioner unit at the movie theater across the street) that persisted for the three nights of my visit. The first night, I found it hard to sleep, but I adapted after a few nights. 
Overall, it's a nice hotel in a great location, but I wish it had better soundproofing.