If you will visit Seattle often or fly out of SeaTac frequently, you might want to consider the inconvenience of traveling by ferry.

I am not familiar with all the micro-climates on the west side of Puget Sound, but I never dried out for the two years I lived in the "convergence zone" about twenty miles north of Seattle.

Also, I saved a lot on taxes when I moved from NYC to WA in 1990--even with the B&O Tax.