Portland is hyper welcoming. While born and raised here, my parents (who were from Asia) moved here about a year prior to my birth and I meet many people living here from abroad each day as I take the transit.
There are subcommunities of virtually every background, whether race, ethnicity, occupation, or interest spread out all over Portland. These can make it welcoming for anyone who visits or moves here.
As for the pretention, I'd say that's more on a personal level for a lot of the hipsters in the city proper. Even then, almost everyone is polite and happy to help you find your way if you get lost (as long as you don't cross to the bad portions of the city, but every city has those). Most of the people you meet will be friendly and courteous, especially if you're a foreigner from Asia or Europe.