I used to live in Bay Area and by far the food up north is way better than SD. If you have a chance, try Japanese noodle at a place called Santa Ramen. Small place that can sit about 20 people and always packed. http://www.yelp.com/biz/santa-ramen-san-mateo
For dim sum, try Koi Palace in Daly City, next to Outback. The place is packed with waiting time at least 1 hour and most expensive. Quality is great so you get top notch food. By far the best dim sum in CA.