In some sense, DL service (for example to Asia) should be better from PDX than SFO, although SFO probably has AF/KLM nonstops to CDG/AMS. For certain other destinations where SFO required a connecting flight to SEA or LAX for a longhaul DL or partner international flight, from PDX you can do the same and first fly to either SEA or LAX. Of course a lot depends on the specifics of your travel patterns.