Portland itself is a very bikeable city and a lot of time/energy is spent to improve and grow this infrastructure. Traffic is getting to the point where cycling is faster for inner-city trips, but as I live outside of the city it's a non-starter because public transportation from my end of town is severely limited.
Seattle doesn't seem nearly as bike friendly, and while it's certainly faster to bike or walk during rush hour, it doesn't seem nearly as safe as Portland. I certainly have no interest in cycling in Seattle, driving is bad enough.