I have heard some of the worst stories about Bellevue BMW (damage to car or work not being done) I won't go there unless I have no choice and I have to drive around it to get to Seattle. Had OK experiences there and pretty good experiences at Seattle.
I am extremely picky about where I take my car for any kind of service so I'll probably never be truly happy at either, but I would seriously stay away from the Bellevue location. I've not heard a good rating for them from anyone period. Just plain awful experiences.