Well, I have lived here for not quite a decade so here's some thoughts.
-if you lived in Portland, you basically understand the social/customs of Seattle - mostly liberal, fighters for social justice, embracers of 15$ minimum wage, etc.
- as you mentioned, the long dark, wet winters are hard but if you are an outdoor person and can ski, snowshoe, etc. there are opportunities that are amazing in the winter.
-Seatac area is more multi-cultural and less expensive than some other areas of Seattle (north side, Bellevue, etc). You could also try Renton area.
-2k a month in that area should be plenty.
some other good things:
- lots of great restaurants, grocery stores with hard-to-get ingredients, etc.
- access to outdoors is second to none. Go to the beach, go kayaking, go hiking, go skiing. Anything. It's all an hour a way. Plus several national parks.
- you mentioned no state income tax. This is juxtaposed by increased car tabs and property taxes. Still a win in my opinion.
- it's *decent* for biking but not great. There are still a lot of distracted drivers IMO
bad things:
-traffic sucks and due to not a lot of money the roads are bad. All of our roads cross water so it makes it challenging with bridges. Commuting N/S is easier than commuting E/W.
- stuff is expensive. Gas, groceries, etc.
- there are a LOT of people in the Seattle-Tacoma area. Seattle proper is not that big but when you add them all in together- it's a boatload.
good things:
-proximity to outdoors and awesome vacation spots: San Juan islands, Canada/Whistler, the national parks, etc.
-good airport HUB. Easy flights to California, Hawaii, etc. Alaska airlines is great.
- music scene (non covid times)
- active hobby/networking groups. While people are mostly introverted and antisocial, there's lots of "clubs" and meetups for people who have hobbies and they are general friendly there.
What else can I answer?