Why shouldn't I move to Portland, Oregon?

I'm feeling a bit stifled in my city and want to move. My priorities are $1500-2000/mo rent and a path to an affordable house (see: picture), a unionised city workforce, good greenspace with an extensive parks system, good biking infrastructure, a good public university, and a good political scene. That leaves Portland, Minneapolis, Chicago, and maybe an East Coast city I haven't researched yet. Of those, Portland is at the top of my list because I'm getting an ocean for Great Lakes prices.

What's bad about the city that makes people move away? Is there a better option in Oregon, especially one that would let me commute into Portland without whatever problems it has?