Dim Sum: Joy Luck Palace (Sunnyvale). LA, the one that’s very good is Five Star Seafood (SGV off of Del Mar). 888 in Valley a little east of that place. Don’t go to Elite, Ocean Star, or mission, IMO. They are kind of on par with Jou Luck Palace. Koi Palace(Daly City) and Flower Lounge(Millbrae), Mayflower(Milpitas) I would stay away from.
Seafood: Newport Seafood(SGV). The restaurants listed above are decent for the Bay Area with Mayflower a notch or two below.
Best Taiwanese street food: Sin Ba La (Arcadia).
Southland Flavor Cafe(Cupertino)
Lastly, in LA, the 626 Night Market is lots of crazy street food.
3 stars in LA crushes 5 stars in other cities in the US.
And yes, I’ve lived 10 years in the Bay Area and the Chinese food pales in comparison.