Yank Sing is perkier than other dim sum restaurants in San Francisco. There is a nicely crisp, snappy, energetic feel to the place that is not entirely accounted for by the steady stream of customers. The same zing is apparent in the food, which is flavourful and arrives swiftly. You will no sooner unfold your napkin than the first cart will roll by, offering steamed dumplings filled with pork, chicken, or shrimp; succulent vegetables; or any of dozens of other treats. Say yes to the asparagus.It draws a big business crowd at lunchtime. This truly local spot features the best dim sum in town, with enough tables to accommodate the masses longing to get in. Terrific dim sum in a bright, elegant setting that is hard to beat. Pace yourself. The carts at Yank Sing never stop coming by with the next delectable treat. Financial District suits fill the restaurant up at lunchtime, but this has a more sedate atmosphere than the Rincon Center branch.