Be prepared to get charged for everything
I stayed there for two nights while going to a training course in Seattle. There are good and bad things about this hotel. I think the bad things outweigh the good things.
Pros: The hotel is nice, in a great location with access to the best parts of downtown. Staff is pretty friendly but its very rigid and businesslike. The beds are very comfy and the rooms are super clean. The gym is also nice and gives ample room to get a solid workout in.
Cons: Pool is ridiculously small, especially for as big as the hotel is. I went both nights to swim and it was packed with people both times. I had my air conditioner down to 60 each night and I still only slept with one sheet. The hotel said they would look at it but it didn't change. Called for valet to get my car but after 20 minutes of waiting they said they forgot... But the biggest disappointment is that the hotel charges for everything! $44 a night for parking, breakfast was so over priced that I went elsewhere. The most frustrating and annoying thing was that they charge $11 a day for wireless internet! Its 2012 for goodness sakes! They will let you use the lobby internet but it was packed with other travelers who were annoyed that they charge so much. 
I won't go back to the Sheraton. There are too many great hotels in Seattle and this isn't one of them.