I love Portland and, while I'm temporarily stuck on the East Coast, I hope to get back there in the next couple of years. Before moving there, however, I also considered Seattle. For me, I like the smaller size and "aging hippy" vibe that still exists in parts of Portland. Seattle, from the one visit I made, feels much more "corporate."
To go off on a tangent for a moment, the Pacific Northwest is overdue for "the big one" -- a devastating earthquake -- and Seattle, especially, could find itself in real trouble when it hits.
A real "doomsday" scenario includes not just an earthquake, but also a resulting tsunami and volcano eruption. I saw a Discovery Channel film on the topic about 10 years ago and, since I have an overactive imagination, it scared the h*ll out of me.

You can read about the topic in this
2002 article. Portland is inland so is, geologically speaking, somewhat safer.
Now, should you live your life in fear of this kind of event? Of course not. There's too many dangerous things in the world and there's no way we can protect ourselves from all of them. But it's something you should certainly be aware of when making a decision about where to live.