This is a tough argument to have because there are different things you can measure. The problem with trying to rate Portland and Oregon is that we drink most of the beer that gets produced here. If you don't live here or travel here, you haven't experienced it and won't be able to give it a fair shake. Oregon has the highest draft beer % and the highest craft % in consumption in the country, and the bulk of beer produced in Oregon gets drank in Oregon. Like was said earlier, there might not be the nationally sought after cache brands like Russian River and DogFish Head, but good beer is part of every day life. Every crappy dive has multiple good local beers. The chain restaurants have 10 oregon beers on tap. The crappy quickymart has 20 different local six packs. The most popular micros around town aren't available outside of the city let alone the state. You can't get Amnesia, Upright, Laurelwood, Roots, or Double Mountain if you aren't around here. McMenamins doesn't sell commercially, they just have dozens and dozens of pubs, brewpubs, event halls, and converted schools you can hang out it in. It's more of a "vibe" thing than can be quantified by comparing breweries.
Also, I think the SD breweries have done a better job of creating "buzz beers" and created more of a national desire for their bottled beers. The Oregon breweries have largely kept their "buzz beer" kind of beers in the local draft beer scene, while companies like BridgePort and Widmer have gone national with affordable six-packs, not trying (until recently) to compete nationally with Russian River, Dogfish Head, etc.