I don't work in Seattle but I was about to, it's 10% cheaper off the bat because of WA's lack of income tax (of course, Amazon also increases base salary in SFBA by about the same amount so it's a wash).

Luxury apartments are much cheaper than SF and South Bay in my experience, and I wouldn't have needed a car. Weather isn't as nice as SFBA probably, but I enjoy the weather around there. Commuting is also pretty straightforward into the suburbs.