This is the same as the Oakland branch. West 25th Ave, San Mateo. We were there for lunch with a group of 14. One of us speaks Shanghainese so the service we got may be better than others. The place was crowded but not overwhelmingly so. There were people waiting on and off but no long lines. They offer a full complement of Shanghainese dim sum. We had most of the usual, soy milk (sweat and salty), fried dough, xiao lung bao, fried dumplings, tea smoked duck, Shanghai style sui mai (stuffed with glutonous rice), Shanghai noodle, pot stickers, and a couple of others.
The xiao lung bao was pretty good, but not the best I've had. My Shanghainese friend said the test is the pan fried dumplings, which according to her is more difficult to make than xiao lung bao. And they make very good pan fried dumplings. The other outstanding dish was the tea smoked duck. Not too fatty with a very good flavor.
This is definitely a place to go if you want Shanghainese dim sum. I would say it's better than Sue Hong at Palo Alto.