I’ve note been to Portland for over 10 years, but I know that various DiSers have been recently so will let them fill in some up to date info. Suffice to say that I absolutely loved the place when I was there - easily one of my top three US cities.
As is Seattle actually, so I would say it’s well worth a visit for at least a couple of days. I was last there a couple of years back and I think it actually gets better with each visit,. You can catch the train up from Portland which is a lovely journey along the water and through forests.
For music/film fans the EMP Museum is a must see - it has so much memorabilia and some lovely hands on stuff:
Chihuly Garden is almost next door and that whole area around the space needle is worth exploring:
At the other end of the city, the area around Pioneer Square and downtown is really historic and has a load of good bars. The underground city tour is fascinating:
The nearby area around Pike Place Market is nice for eating, drinking, shopping, watching the sun go down:
Edited to get the links to work…