In terms of service work, I’ve only used the Bellevue SC and couldn’t say enough good things about them. The best compliment I can probably give them is that they always make me feel like a valued customer. I’m big on communication and they do a really good job there, even on little things like post-service follow up. I’ve been happy with the quality of their work too. Even on loaners, they’ve always given me another Tesla one way or the other (there was one time where they didn’t have one available, but completely arranged for a rental Tesla at a nearby Enterprise).
I do also have a positive impression of the Seattle SC. When I was deliberating whether to buy a Model S last year, I had multiple test drives and visits at both SCs, and they were all so awesome and accommodating. The Seattle SC staff was great and at one point even let me test drove an S by myself. The Bellevue SC is just more convenient for me, but, if I had to, I would feel comfortable taking my cars to the Seattle one based on my prior experience with them.