I've had the rare privilege to meet the Pinball map creator (or at least one of them), an awesome person that has been maintaining this project for a long time. Definitely give them some support if you're a Pinball fan. Portland was the original base location and then IIRC they expanded to other cities. Portland's reputation as the pinball capital of the world is well founded.
I thought Chicago was the pinball capital of the world, given every pinball manufacturer basically ever was based there.
I prefer the pinball scene in Milwaukee. Seemingly every neighborhood has at least a few relaxed, cozy bars with a decent number of machines in the back room, and there are also a few decent venues that are open to minors.
I don't know Portland as well, but based on what little time I've spent there it seemed like the situation was more similar to what it's like in Milwaukee. I've stumbled across some great old classic machines when I was there.