Today, the San Gabriel Valley hosts some of the most diverse styles of Chinese cooking in North America: Cantonese, Hong Kong-style cafes, Shanghainese, Muslim, Sichuan, Hunan, Taiwanese, etc. For those unfamiliar with the different styles of Chinese cooking, China is a very large country with different growing conditions. Climate and geography heavily influence the type of cooking in each area. For example, in the North, it is too cold and dry to grow rice, so Northern Chinese cooking uses a lot of wheat.
Finally, there are a good number of vegetarian restaurants around because pious Chinese Buddhists are vegetarians. Most people I know like those restaurants. You can order stuff like imitation chicken, duck, kidneys, and so on. Yes, you can order imitation kidneys. I generally don't like the imitation foods very much because they are a bit too salty for me because I'm very sensitive to salt.
As a general rule of thumb: avoid ordering dishes from areas other than the restaurant's specialization (e.g. don't order a rice dish in a Northern Chinese restaurant). It's like asking an Italian chef to prepare sushi.