here's my general take as someone originally from overseas (Aussie of Chinese descent) but in States last 6 years..
feel free to chime in or correct me.. generalizations of course
NYC metro - so-so, the supposed general 'melting pot.' feels more like a tossed salad (no pun).. ie entire neighborhoods/towns of a race/religion. also still more Euro-centric than most cities due to history etc.. that said since the metro area is so HUGE, you really can find your own group, and enjoy the City in your own terms.
LA metro - just okay.. yes lots of Asians, but maybe the Hollywood media portrayal also exists with locals so it balances out..maybe slightly better than NY since it feels less Euro-centric than Northeast overall?? Asian influences more prevalent, and also much more laid back.
PHILADELPHIA - surprisingly friendly, in a blunt, jovial sort of way..ie make Asian jokes then buy you a beer.. self-deprecating, insults with good intentions if that makes sense lol.
BOSTON - (my college town) exact opposite of Phila.. supposedly 'progressive'.. say all the right things, but practice opposite..probably worst city on the list (again, just generalizing)
SAN DIEGO - very receptive..jackpot(?), lol..must revisit soon. uhm, can't think of anything bad to say. closes early? who cares when your outdoors all day.
CONNECTICUT (Fairfield County) - generally friendly (where I work).. though technically part of NYC metro, I separated it, since I generally notice a genuine 'who cares' attitude somewhat similar to San Diego. People are more focused on 'what can you do' as opposed to race, despite its 'waspy' reputation from outsiders.
PHOENIX/SCOTTSDALE, AZ - mixed bag.. everyone here is JACKED lol.. As long as you are built, jacked shouldn't have too much of an issue.
CHARLOTTE, NC - friendly.. coming from NYC area, NC still gets reputation of hicks not welcoming of outsiders.. found it to be the TOTAL opposite. very welcoming and it seems in the South in general, ironically race isn't as big an issue, though I obviously can't speak for other races/experiences.
MIAMI, FL - not as welcoming.. probably because not too many Asians??..
ATLANTA, GA - Friendly city overall...Kinda like Charlotte..race doesn't seem as huge factor as in New England.. I've heard of the "Nice to your face only" mantra about certain cities in the South, but don't think I experienced much of that.. then again was only here a couple weeks so who knows..
LAS VEGAS - good. mix between LA and San Diego vibe..but its such a transient city.. so who really knows.. met up with some locals who worked in the Cirque shows, very down to earth and generally receptive/could care less about race so long as good peeps.