Though SF is no New York, it is notably more urban than Portland. San Francisco is physically more strikingly beautiful than Portland, with magnificent views of the bay and ocean from the hills. Portland is surrounded by beautiful forests and parks, but so is SF - you can get from downtown SF into the middle of a quiet redwood forest in about 25 minutes, and the coast, north and south, is far more accessible than it is in Portland[1]. While SF has a severe problem with street addiction and mental illness, so does Portland, and SF does still have extensive walkable urban and semi-urban neighborhoods. Golden Gate Park, the Presidio, and Crissy field are just a few of the outdoor options within the city. There are also plenty of options to live in lower density, SFH neighborhoods with small backyards. Culturally, San Francisco is much more diverse than Portland - SF actually ranks first among US cities in the number of languages spoken by 1000+ households. Portland is overwhelmingly white and has a historical hostility toward ethnics and immigrants (some believe that the anti-Californian sentiment has roots in hostility toward Catholic and darker skinned immigrants) - and, ironically on the other side of the political spectrum, a lot of immigrant or first generation communities are actually uncomfortable with predominantly white, left wing progressive politics. Immigrants may be more likely to find a community in SF than Portland.
[1] I surf, which makes Portland a hard pass for me, though that's a bit too niche for a general comparison.