The Sharaton still is paired up with PAX, but many of the Thursday night and Monday night rooms are already sold out, so you might not see it if you are looking at a block of rooms with one of those nights on it.
We reserved Crowne Plaza Hotel for PAX this year. I have never stayed there before, so I'll see how it is.
For SakuraCon this year I am staying at the Seattle Renaissance Hotel. I stayed there once before, too, and it was awesome. I don't think it's paired up with PAX, but I figured I'd give my 2 cents. I also like the Camlin alot, but you have to be a WorldMark member to stay there. (My friend is, but I'm not, so it's only when I am staying with her.) We stayed there a bunch of years in a row for SakuraCon, and the bellhop always would remember us from previous years.
I've stayed in the Hilton a couple of times, it's my favorite for closeness, since there is the underground path to the convention center, but it wasn't amazing or anything as far as the hotel itself goes. (Though not bad either) Same goes for the Roosevelt, stayed there a couple times, it's certainly decent, but not outstanding or anything. (Though I like their restaurant a lot.) I guess the least favorite hotel I have stayed in was the W. It wasn't terrible or anything, just kind of cramped and old. (But if I remember correctly, it was also cheeper.) And we were room-stuffing a bit, so it's just a plus when the room isn't cramped.
All in all, I have never had a bad experience with any of the hotels I have stayed in, there are just the couple that I like slightly better.