I moved to Seattle from the SF Bay Area 20 years ago, and it has been a great move overall. Lots going on technically especially IT - Microsoft (Redmond), Google (Kirkland), Amazon (Seattle), Starbucks (Seattle), CostCo (Issaquah), Boeing (Everett & Renton), and many MANY others.
You can search housing costs, food costs, etc but you can't find good information on traffic. Traffic has gotten progressively worse here over the time I've been here - but I've been here so long, I can't compare it to a current-day commute in the Bay Area or LA.
If you're in doubt, take a week, fly up for a vacation, beat the LA heat, and check out the area for yourself. Although... this week we're in the 90's - very unusual for Seattle. A nice time for a day trip up to the mountains (35 minute drive), or a dip in Lake Washington.